In psychotherapeutic and lesbian popular culture literatures, there is an assumption that female same-sex couples are overly close and lack boundaries, a concept called “fusion.” Empirical efforts have yet to demonstrate whether fusion is experienced more often among women in same-sex relationships than among men in same-sex relationships or among men and women in heterosexual relationships. Furthermore, research on the topic has yet to fully incorporate feminist perspectives that challenge assumptions that high levels of closeness in and of themselves are problematic. Our study employed measures of Inclusion of Other in Self (Aron, Aron, & Smollan, 1992) to examine the distribution of indicators of fusion among 76 women and 58 men in same-sex relationships and 1,221 women and 285 men in heterosexual relationships. Women in same-sex couples differed from the other groups on only one indicator of fusion—they were more likely to desire less closeness in their relationships, even though their current relationships were rated as close as other types of relationships. Our study suggests that widely held assumptions that women in same-sex couples experience and idealize pathologically high closeness are not accurate.