Beyond the Dyad: a Review of the Novel Insights Gained From Studying Consensual Non-monogamy

Abstract

Purpose of Review
The purpose of this review is to highlight the major advancements in our understanding of consensually non-monogamous (CNM) relationships—or intimate relationships between three or more people who are non-exclusive sexually and/or emotionally. We aim to review key insights from research on the benefits (i.e., diversification of need fulfillment) and challenges (i.e., continued stigma) of CNM relationships and how research on CNM highlights some limitations of the existing theories of relationships.

Recent Findings
The last two decades have seen a trend towards increasing diversity of family structures. Although monogamy remains the most common relationship structure, CNM relationships are increasing in prevalence and in interest to both lay people and researchers. Recent research has begun to uncover novel insights into who is more likely to be drawn to and engage in CNM, how CNM relationships compare to monogamous relationships, and the potential benefits and challenges of engaging in CNM relationships.

Summary
While people in CNM relationships still experience stigma, for those who desire such relationships, CNM can be a viable and healthy alternative to monogamy, and may even help people meet more of their needs through diversifying need fulfillment across multiple partners. Despite this, many existing relationship theories are not inclusive of CNM relationship experiences and aspects of existing theories of positive relationships and sexuality may not extend to people in CNM relationships. Moving forward it is important to consider whether our concepts and measures are inclusive to people in diverse relationships, including those in CNM relationships.

Full text

FEMALE SEXUAL DYSFUNCTION AND DISORDERS (A STANTON & T LORENZ, SECTION EDITORS)
Beyond the Dyad: a Review of the Novel Insights Gained From
Studying Consensual Non-monogamy
Rhonda N. Balzarini
1
&Amy Muise
2
Accepted: 5 November 2020
#Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract
Purpose of Review The purpose of this review is to highlight the major advancements in our understanding of consensually non-
monogamous (CNM) relationships—or intimate relationships between three or more people who are non-exclusive sexuallyand/
or emotionally. We aim to review key insights from research on the benefits (i.e., diversification of need fulfillment) and
challenges (i.e., continued stigma) of CNM relationships and how research on CNM highlights some limitations of the existing
theories of relationships.
Recent Findings The last two decades have seen a trend towards increasing diversity of family structures. Although monogamy
remains the most common relationship structure, CNM relationships are increasing in prevalence and in interest to both lay
people and researchers. Recent research has begun to uncover novel insights into who is more likely to be drawn to and engage in
CNM, how CNM relationships compare to monogamous relationships, and the potential benefits and challenges of engaging in
CNM relationships.
Summary While people in CNM relationships still experience stigma, for those who desire such relationships, CNM can be a
viable and healthy alternative to monogamy, and may even help people meet more of their needs through diversifying need
fulfillment across multiple partners. Despite this, many existing relationship theories are not inclusive of CNM relationship
experiences and aspects of existing theories of positive relationships and sexuality may not extend to people in CNM relation-
ships. Moving forward it is important to consider whether our concepts and measures are inclusive to people in diverse
relationships, including those in CNM relationships.
Keywords Consensual non-monogamy .Romantic relationships .Sexuality .Need fulfillment .Relationship quality .Stigma
The last two decades have seen rapid changes in Western
families, with a trend towards increasing diversity of fam-
ily structures. Longer life spans [1], along with increases
in inter-racial, inter-religious, and same-sex marriages [2],
and steep fertility declines [3,4] are only a few of the
social trends that are increasing the diversity of families
and relationships. However, the nuclear monogamous
family remains a powerful normative ideal in much of
the Western world [5,6], and people who do not follow
this pattern may be considered deviant or not even fami-
lies at all [7,8]. While monogamy remains the most com-
mon romantic relationship arrangement in most parts of
the world, consensual non-monogamy (CNM)—or inti-
mate relationships between three or more people who
are non-exclusive sexually and/or emotionally [9,10]—
is increasingly prevalent and becoming more visible in
mainstream media and in societies as well [11]. In fact,
public interest in CNM relationships has increased dra-
matically in recent years, with searches for information
on polyamorous relationships, one type of CNM relation-
ship,beinglistedamongthetop10relationshipqueries
by Google in 2017 [12]. Increased interest in CNM is
apparent not only in rising Google searches ([12]; also
see [13]) but also in heightened media attention, with
shows like “You Me and Her”and “Unicornland,”as well
as the inclusion of polyamory as a relationship orientation
This article is part of the Topical Collection on Female Sexual
Dysfunction and Disorders
*Rhonda N. Balzarini
rnb85@txstate.edu; balzarinir@gmail.com
1
Department of Psychology, Texas State University, San
Marcos, TX 78666, USA
2
Department of Psychology, York University, Toronto, ON, Canada
Current Sexual Health Reports
https://doi.org/10.1007/s11930-020-00297-x

on the popular dating website OKCupid [14],andinmore
researchers examining the prevalence and outcomes of
CNM arrangements [11,15].
Over the past decade, research on CNM relationships has
gained a greater presence in relationship and sexuality re-
search [16] and has begun to uncover novel insights into
who is more likely to be drawn to and engage in CNM, how
CNM relationships compare to monogamous relationships,
and the potential detriments (e.g., stigma) and benefits (e.g.,
diversified need fulfillment) of engaging in CNM relation-
ships. This research suggests that for those who desire such
relationships, CNM can be a viable and healthy alternative to
monogamy (e.g., it can be just as satisfying as a monogamous
relationship; [15,17•]), and having multiple simultaneous re-
lationships can help people meet more of their fundamental
needs (e.g., [18–20]). The purpose of this review is to high-
light the major advancements in our understanding of CNM
relationships based on the most recent work in the field, dis-
cuss the ways in which insights from research on CNM rela-
tionships raise questions about the inclusivity of relationship
theories (e.g., commitment being equated with monogamy or
exclusivity), and challenge the boundary conditions of
existing theories (e.g., attachment theory; [21]). Through this
review and identification of novel advancements in the field,
we provide a summary of the current research on CNM rela-
tionships and discuss directions for future work.
Prevalence and Engagement in CNM
Past research suggests that a non-trivial number of people
have engaged in or are interested in CNM relationships. For
example, research using nationally representative samples of
people from the USA and Canada has shown that approxi-
mately 4–6% of individuals report currently being in a CNM
relationship [22,23]. And, far more people have experience
with or interest in CNM, with more than 20% of Americans
indicating previous participation in some form of CNM in
their lifetime [23] and with CNM sexual experiences (e.g., a
threesome) emerging as the most common sexual fantasy peo-
ple report [24]. Furthermore, the prevalence of experience
with CNM is even higher among people who identify as bi-
sexual, with approximately 33% reporting previous participa-
tion in CNM [23].
Importantly, CNM is an umbrella term for various non-
monogamous relationship agreements that differ based on the
degree to which sexual and emotional needs are consensually
fulfilled outside of a romantic dyad [16]. The three types of
CNM relationships that are often delineated are swinging, open,
and polyamorous relationships [15,25,26]. Swinging relation-
ships involve temporarily swapping or exchanging partners
among couples, often in the context of a specific social event
[26,27]. Open relationships involve extradyadic sex without
love and without a romantic partner’s participation [16,26,
28,29]. Polyamorous relationships permit loving more than
one person, and typically consist of multiple, emotionally close
relationships [16,26]. Although CNM affords emotional and
sexual connections with multiple partners simultaneously, poly-
amory tends to involve close emotional with additional partners
than swinging and open relationships, which tend to be primar-
ily about sexual openness [5,15,30,31].People in CNM rela-
tionships often have their own unique agreements with partners
and CNM relationship can take on many different structures,
but one of the most common configurations, at least for people
in polyamorous relationships, is a primary-secondary relation-
ship configuration [17•,32]. In this configuration, a primary
relationship is between two partners who typically share house-
hold finances, live together, and who are married, and relation-
ships with partners beyond the primary relationship are often
referred to as secondary, non-primary, or tertiary partners [17•,
27,33•]. Although less research has examined the configura-
tions of people in open and swinging relationships, because
these relationships primarily involve extradyadic sexual en-
counters, they often follow a similar structure with one partner
serving as a primary partner and the other(s) as non-primary
(e.g., [34,35]).
Challenges of Deviating Beyond the Dyad:
Stigma Towards CNM Relationships
Despite the growing prevalence, people in CNM relationships
are stigmatized [36]. For example, 26–43% of people in poly-
amorous relationships report experiences of stigma and dis-
crimination [37]. To illustrate how pervasive this is, in a series
of studies [9], monogamous targets were rated more positively
than people in CNM relationships in relationship-relevant and
relationship-irrelevant domains. That is, monogamous cou-
ples were perceived to not only be more trustworthy and pas-
sionate but also to be more likely to pay their taxes on time, to
floss their teeth, and to walk their dog [9]. However, some
forms of CNM, specifically polyamory, are viewed more fa-
vorably than other forms, such as swinging or open relation-
ships [26,38]. One reason that has been proposed for why
people in CNM relationships continue to face stigma is be-
cause these relationships are associated with greater perceived
promiscuity and likelihood of having sexually transmitted in-
fections (STIs). In fact, research suggests that attitudes to-
wards people in CNM relationships are related to the percep-
tion that people in CNM relationships will spread STIs (e.g.,
among polyamorists, see [39]; and CNM more broadly, see
[9]). Indeed, in a study [38] examining stigma towards people
in the differing types of CNM compared to monogamists
showed that people in monogamous relationships are per-
ceived to be the least promiscuous and to have the lowest
STI rates while swingers were perceived as the most, and
Curr Sex Health Rep

those in polyamorous andopen relationships were in-between.
Results also suggest that stigma towards people in CNM rela-
tionships was partially attributed to the perception of STI risk
but not to perceptions of promiscuity—suggesting stigmatiza-
tion towards people in CNM relationships, in part, was a func-
tion of perceptions of STI risk.Notwithstanding these percep-
tions, people in CNM relationships are less likely to contract a
sexually transmitted infection than people who identify as
monogamous (see [40] for a review), and CNM individuals
are more likely to engage in safer sex practices (e.g., using
condoms and getting tested for STIs) than people in monoga-
mous relationships [41,42]. Part of the reason for these dif-
ferences is that while people in CNM relationships might en-
gage in sex with multiple partners, all partners are aware of the
arrangement and can have an open discussion about their sex-
ual health and extradyadic engagement. In the USA, 20–25%
of people in monogamous relationships engaged in extramar-
ital sex [43–45] and people who are in monogamous relation-
ships are less likely to practice safer sex in these encounters
than CNM individuals [40,41,46]. Therefore, with infidelity
occurring in a reliable minority of romantic relationships, ap-
prehension about CNM relationships and concern about STI
risk might be overblown while concern for STI risk among
people in monogamous relationships may be understated.
This idea is consistent with recent findings that suggest that
monogamy might be less effective at preventing STIs than
expected (see [40,41]).
Stigma about CNM relationships also extends to the idea
that opening up a relationship or having multiple romantic or
sexual partners indicates that an existing or primary relation-
ship is unsatisfying. However, a growing body of research
suggests that people in CNM relationships are as equally sat-
isfied with and committed to their relationships as individuals
in monogamous relationships [15], and there is evidence that
individuals in CNM relationships report higher sexual satis-
faction and passion [47] and lower jealousy [48,49] than
monogamists. Although there is growing evidence that people
in CNM relationships report at least as much relationship
quality on average as monogamous couples, CNM arrange-
ments involve multiple partners and relationship and sexual
outcomes across partner can differ. Recent research has found
some differences between primary and secondary partners.
For example, individuals in polyamorous relationships report
being more satisfied with, committed to, and invested in their
relationships with primary partners compared to secondary
partners, but, they report higher sexual frequency [17•,33•],
greater sexual satisfaction [47], and met sexual ideals [50]
with their secondary partner compared to their primary part-
ner. Research comparing reports for polyamorous partners to
monogamous partners suggests that reports for primary part-
ners in polyamorous relationships often mirror reports for mo-
nogamous partners. More specifically, a study comparing re-
ports for polyamorous partners to monogamous partners
found that reports for primary partners and monogamous part-
ners do not differ with regard to commitment or investments,
but people in polyamorous relationships tend to report higher
sexual frequency, more stigma (e.g., less acceptance from
friends and family), and stigma management (e.g., maintain-
ing relationships in secrecy) with secondary partners com-
pared to reports for monogamous partners [17•].
Broadening Our Understanding of Need
Fulfillment
One of the potential benefits of engaging in CNM relation-
ships is the diversification of need fulfillment across multiple
partners simultaneously. For example, in her book based on
her experiences as a couples’therapist, Esther Perel [51]talks
about how people’s expectations for their romantic relation-
ships have changed over time such that people now expect
their romantic partners to meet several higher order needs,
such as personal growth and emotional and sexual fulfillment.
Perel’s[51] ideas are in line with a model recently proposed
by Finkel and colleagues [52]—the suffocation model of
marriage—which argues that in Western culture, today rela-
tive to the past, people expect more from their relationships,
and although people who can meet these high expectations
can flourish, many people are not investing the time and en-
ergy to meet the high expectations they place on their relation-
ships. The authors describe this as climbing mount Maslow
without sufficient oxygen—meaning, people are aiming to
meet higher order need for fulfillment and self-actualization
without devoting the proper resources [52]. In response to this
model, Conley and Moors (2014, [53]) proposed that adopting
the tenets of CNM relationships and offloading some needs to
additional partners could help strengthen or oxygenate a
relationship—serving as one path towards greater need
fulfillment.
Recent qualitative research with people in CNM relation-
ships found that the most cited benefit of CNM reported by
42% of the sample was diversified need fulfillment [54•]. In
fact, in a study that followed people who were considering
opening up an existing relationship found that one reason
people seek out additional partners is to meet needs that are
unfulfilled in their current relationships [55]. In this study,
people who actually opened up to a CNM relationship (com-
pared to those who did not) reported greater sexual satisfaction
over the course of two months, and this was especially true if
they opened up their relationship to address sexual incompat-
ibilities with their primary partner [55]. Indeed, past research
has shown that relationships with primary partners are char-
acterized by more commitment, investments, and satisfaction
and greater communication than relationships with secondary
partners [17•,33•], and people tend to rate their primary part-
ners as more desirable long-term partners [56]. But,
Curr Sex Health Rep

relationships with secondary partners are characterized by a
greater percentage of time spent on sexual activity [17•,33•],
more eroticism [18], more passion, and greater sexual satis-
faction [47] and yet, secondary partners are considered less
desirable long-term mates [56]. Taken together, this work pro-
vides preliminary evidence that primary and secondary rela-
tionships may meet different needs, with secondary relation-
ships being characterized as more sexually fulfilling while
primary relationships might meet more emotional needs.
If individuals in CNM relationships can experience higher
need fulfillment through having their needs met across multi-
ple, simultaneous relationships, it is possible that the diversi-
fication of needs could be associated with feelings of satisfac-
tion in their relationships. Mitchell and colleagues [19]pro-
posed three different models to explain the role of need ful-
fillment in CNM relationships. The proposed models posit
that having needs met in one relationship could either (1)
detract from the relationship satisfaction in another, concur-
rent relationship (e.g., contrast model), (2) be associated with
greater satisfaction in another, concurrent relationship (e.g.,
additive model; [57]), or (3) be associated with greater satis-
faction in another relationship, but particularly when need
fulfillment in the initial relationship is low (e.g., compensation
model; [58]). Several studies have examined the effects of
need fulfillment in CNM relationships, but support for the
different models has been mixed. For example, Mitchell and
colleagues [19] found that the extent to which one partner met
aperson’s needs was unrelated to satisfaction or commitment
with another partner (inconsistent with the additive or contrast
models) and need fulfillment across various needs assessed
wasconsistentlyhighwithbothpartners(inconsistentwitha
compensation effect as people in CNM relationships were
fulfilled by both partners). However, in a study [20]thatin-
vestigated sexual need fulfillment specifically, when a prima-
ry partner was more motivated to meet a person’s sexual
needs, this was associated with greater sexual satisfaction with
their secondary partner (evidence for the additive model),
though greater sexual need fulfillment with a secondary part-
ner was associated with less satisfaction with a primary part-
ner (evidence for the contrast model). Similarly, a recent study
examining sexual and emotional need fulfillment [18]found
that when polyamorous individuals reported more eroticism
(i.e., feelings of arousal, passion, lust, sexual pleasure) with
their primary partners, they reported greater sexual satisfaction
with their secondary partner (evidence for the additive model)
though greater eroticism with a secondary partner was associ-
ated with less sexual satisfaction with a primary partner (evi-
dence for the contrast model). In contrast, ratings of one part-
ner’s nurturance (e.g., feelings of intimacy, warmth, and love)
were not associated with sexual satisfaction in other, concur-
rent relationships suggesting that loving, caring feelings with
one partner were not associated with sexual satisfaction with
the other partner [18].
The findings on need fulfillment across relationships sug-
gest that concurrent relationships can have null, negative, or
positive effects on each other, and thus, an important future
direction will be understanding when, and under what circum-
stances, relationships with concurrent partners benefit or de-
tract from relationship quality with the other. Although there
is limited research to draw on at this time, it might be the case
that certain qualities from a primary partner influence the abil-
ity to maximize the benefits of seeking out multiple, simulta-
neous relationships. For example, Muise and colleagues
(2019, [20]) found that when people in CNM relationships
had a primary partner who was more communal (e.g., moti-
vated to meet their needs), they were able to be more satisfied
in their secondary relationships—suggesting that having a
communal primary partner (or other features of the primary)
can help people maximize the benefits of multiple concurrent
relationships. It also might be the case that people can mitigate
the detriments through their own actions. For example,
Mogilski and colleagues (2017, [56]) found that CNM partic-
ipants reported talking about their extra-dyadic sexual experi-
ences and downplaying these sexual experiences more often
with their primary partner compared to their secondary part-
ner, perhaps because sexual engagement is higher with this
partner and thus restricting information may help individuals
meet their needs while also maintaining their relationship with
their primary partner.
Expanding Theories of Relationships
Theoretical Advancements
One of the unique benefits to studying CNM is that it informs
and can challenge the boundaries of our current relationship
theories. Indeed, scholars have recently argued that many the-
ories in the psychology of relationships and sexuality include
conceptualizations of relationship quality that have an implicit
assumption that monogamy is the most desirable relationship
style [47]. As such, most of the theories used to understand
and predict relationship processes have been tested with a
monogamous sample and it is not clear how these might ex-
tend to sample of people who are navigating multiple relation-
ships. There are two illustrative examples of this in the field of
relationship and sexual science. First, one of the standard ap-
proaches for assessing love in relationships involves asking
participants about their passionate and companionate love for
their partner [59,60]. However, this approach may inhibit
researchers from understanding passionate and companionate
love in polyamorous relationships. For example, the
Passionate Love Scale [60] includes the item “I’d get jealous
if I thought [my partner] were falling in love with someone
else.”This item has a built-in assumption that more jealousy
about a third party is equivalent to more passionate love; how-
ever, researchers point out that this may not be true for
Curr Sex Health Rep

individuals in CNM relationships who may actually experi-
ence positive affect in response to a partner finding a new
relationship (i.e., people in polyamorous relationships may
feel positive emotions when a loved one pursues other rela-
tionships sexually or emotionally; e.g., [48,49,61,62]). As a
result of this assumption, participants who are in CNM rela-
tionships would score lower on passionate love due to lower
levels of reported jealousy despite experiences of passion with
partners (see [47]). To address these issues, recent research
has re-conceptualized the concepts of companionate and pas-
sionate love developing a measure that assesses eroticism and
nurturance and that is applicable to both those in monogamous
and CNM relationships [18].
Second, attachment theory is arguably among the most widely
studied theories of romantic relationships. Attachment theory
posits that romantic bonds are important sources of support,
emotional stability, and safety and that secure attachment comes
from repeated exposure to safe and supportive care [63]. A small,
but growing, body of research has found that individuals in CNM
relationships report high relationship quality, open communica-
tion, high levels of honesty, trust, and intimacy, and low levels of
jealousy (e.g., [17•,33•,48,56]), all qualities that are analogous
to those that characterize a secure attachment [64]. However, one
component that differs is relational exclusivity—or the assump-
tion that pair bonding and love occurs among those who are
sexually and romantically exclusive with their partners. In fact,
sexual and romantic exclusivity are often conflated with ideas of
love among attachment theorists (e.g., [65–67]). Therefore, ex-
amining attachment among people in CNM relationships and
across partners allows for novel theoretical testing of the bounds
of attachment theory—and other theories—given that CNM re-
lationships afford people the opportunity to form deep emotional
and sexual bonds with more than one person. Indeed, despite the
theoretical assumptions (e.g., assuming pair bonds occur among
exclusive, romantic dyads), recent work suggests that people in
CNM relationships have similar attachment orientations with
each of their partners (though greater security was reported for
their primary partner) and report greater security [68] compared
to established norms among monogamist [21]. This work and
other works (e.g., evidence for diversifying need fulfillment; [51,
52]) beg the question of the built-in assumptions in our theories
while providing novel tests of the boundaries of existing theories.
Conclusions and Future Directions
The research on CNM to date suggests that a non-trivial
number of people are interested in or have experience
with CNM relationships, and that CNM relationships can
be a healthy and viable alternative for those who are in-
terested in relationships that extend beyond the monoga-
mous dyad. Past work suggests that engaging in CNM can
be associated with important benefits, such as the
opportunity to diversify need fulfillment across partners,
but also some challenges, such as enduring stigma and
misunderstandings. Despite the burgeoning research in
this area, many questions remain unanswered and are im-
portant future directions for researchers to pursue.
First, the bulk of the data on CNM relationships, as
with monogamous relationships, includes people who
are highly satisfied with their relationships. Therefore,
we have little information about people who experience
challenges with CNM or about people who have ended
CNM relationship. Due to the stigma around CNM rela-
tionships, an early goal of researchers seemed to be to
compare CNM relationships to monogamous relationship
to determine if engaging in CNM was, in fact, associated
with more negative relationship and personal outcomes.
Now that we have evidence that CNM relationships are
at least as satisfying as monogamous relationships and
can be a healthy, viable alternative for those who are
interested, future researchcouldexploremorenuanced
questions about the benefits and challenges of navigating
relationships with multiple partners. Recently, a group of
prominent CNM researchers have joined forces to develop
a Multi-partner Relationship Maintenance Strategies Scale
(MRMSS) that will assess how people who pursue multi-
partner romance (e.g., polyamory, open relationships,
swinging, plural marriage) regulate their own and their
partners’sexual and intimate interactions with other peo-
ple. The researchers seek to understand the practices that
help people resolve or agitate common sources of conflict
among romantic partners and rivals within multi-partner
relationships (e.g., jealousy, partner rivalry, disease trans-
mission, partner abandonment).Additionally, the growing
body of research on CNM has either utilized existing
scales that have been created with the implicit assumption
that monogamy is the most desirable relationship style
[47] or has had to create their own scales to more ade-
quately capture relational processes beyond the dyad (e.g.,
[18]). This is a limitation of much of the existing literature
that aspects of existing theories of positive relationships
and sexuality may not extend to people in CNM relation-
ships. Moving forward, it is important to think about
whether our concepts and measures are inclusive to peo-
ple in diverse relationships, including those in CNM rela-
tionships. This might mean stepping back and re-
examining how we ask about commitment (do we assume
commitment equates with monogamy?) and how we ask
about infidelity (do we assume any extradyadic relation-
ships are cheating?) and other major constructs of interest.
Therefore, there are opportunities for future research to
expand our understanding of relationship quality and
maintenance by re-considering the role of monogamy
and by testing whether tenets of CNM relationships have
broad implications for understanding need fulfillment.
Curr Sex Health Rep

Funding This work has been supported by a Mitacs Accelerate and
Elevate Grant awarded to Rhonda Balzarini and an Insight
Development Grant from the Social Science and Humanities Research
Council (SSHRC) awarded to Amy Muise and Rhonda Balzarini.
Compliance with Ethical Standards
Conflict of Interest Rhonda Balzarini declares the receipt of grants from
Mitacs and the Social Sciences and Humanities Research Council during
the preparation of this paper.
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