Family research has highlighted an increasing fluidity in understandings of family with many recent studies focussing on personal relationships and on the relational character of family phenomena in diversifying familial contexts. In this study we explore how personal understandings of family are constructed by balancing individual preferences and general rules of kinship. This article focuses on who is considered a family member by wives and husbands in opposite-sex couples after the first years of (the first) marriage. The data consist of qualitative interviews with 32 individuals, women and men from 16 couples, living in Southern Finland. Information on family EUROPEAN SOCIETIES 2 conceptions was collected using the Family Network Method (FNM) questionnaire completed at the end of interviews. Our results show that despite the conventional family structure within which interviewees live-that is, a married opposite-sex couple, most often with childrenunderstandings of family vary greatly between spouses. The family form does not determine interviewees' views on who constitutes family. Rather, family understandings draw from balancing between perceived emotional closeness, genealogical proximity and cultural expectations, producing different and sometimes conflicting tendencies of family belonging delineated in our analysis.