Device-to-device (D2D) communication standardiza- tion is underway and considered as one of key technologies in the 5G ecosystem. Eavesdropping is a well-known security risk for D2D communications. Thus, ensuring information security for both cellular users (CUs) and D2D pairs in an underlay network is quite challenging. In this paper, we look into the problem of physical-layer secure transmission jointly with resource allocation in D2D communications. We leverage social-domain and frame a coalitional game approach, enabling multiple D2D pairs to share CU spectral resource. We assume multiple eavesdroppers based practical scenario to maximize system sum-rate, and to ensure information confidentiality for both CUs and D2D pairs. More- over, we prove our proposed algorithm stability, convergence, and computational complexity. The simulation results establish the effectiveness of our proposed approach that not only maximizes the sum-rate (i.e., 10% to 60%) but also improves the secrecy capacity (i.e., 20% to 67%) in comparison to the baseline schemes.