In today’s digital age, the pervasive presence of digital technology (e.g., mobile devices, social media platforms) has profoundly impacted our social lives. These technologies offer many opportunities for the initiation, maintenance, and even the dissolution of romantic relationships, but also introduce challenges. It has become increasingly complex to navigate the intricacies and vulnerabilities inherent to (building) romantic connections in online settings. As a consequence, hurtful experiences may lie in wait. This dissertation provides a thorough exploration of recent research findings, including my own, on various forms of harmful technology use that may occur in adults’ romantic relationships. Specifically, this dissertation focuses on six distinct phenomena: harmful sexting, catfishing, partner phubbing, electronic partner surveillance, online infidelity, and ghosting. Drawing from prior research findings as well as my own, each phenomenon is examined through the lens of (1) its conceptualization, (2) the characteristics of individuals involved in the behaviour, and (3) the underlying mechanisms and motivations driving these harmful technology practices.