Assuming isomorphism between heterosexual and homosexual relationships may preclude a contextual understanding of gay male monogamy and extra-dyadic sex that may otherwise remain perfunctory. This study sought to explore the experiences of gay men who engaged in extra-dyadic sex outside their primary relationships. Based on qualitative interviews with eight gay men, this study may shed light on the relational structures and processes of same-sex unions. Several strategies including compartmentalization, boundary affirmation and secretiveness were reported to be utilized to preserve emotional monogamy and primary relationship quality. Such findings may bear relevance to therapeutic practitioners working with this group that may challenge normative relationship conventions.