--- - |2 Abstract Drawing on an analysis of qualitative interview data from a study of formalized same‐sex relationships (civil partnerships) this paper examines the enduring significance of marriage and family as social institutions. In doing so, it intervenes in current debates in the sociology of family and personal life about how such institutions are undermined by reflexivity or bolstered by convention. Against the backdrop of dominating sociological frames for understanding the links between the changing nature of marriage and family and same‐sex relationship recognition, the paper analyses the diverse and overlapping ways (including the simple, relational, strategic, ambivalent and critical ways) in which same‐sex partners reflexively constructed and engaged with marriage and family conventions. My analysis suggests that instead of viewing reflexivity and convention as mutually undermining, as some sociologists of family and personal life do, it is insightful to explore how diverse forms of reflexivity and convention interact in everyday life to reconfigure the social institutions of marriage and family, but do not undermine them as such. I argue the case for recognizing the ways in which ‘reflexive convention’, or reflexive investment in convention, contributes to the continuing significance of marriage and family as social institutions. - 'The British Journal of Sociology, Volume 69, Issue 3, Page 626-646, September 2018. '