An evolutionary psychological perspective on friendship suggests that sex and relationship status may predict people’s motivations for initiating, selecting, and dissolving opposite-sex friendships. Men and women are predicted to differ psychologically in domains in which they recurrently faced different adaptive problems over human evolutionary history (Buss, 1995). Women, for example, have faced a 9-month obligatory investment to produce a child. Men have not. Historically, the direct reproductive benefits in offspring production from gaining sexual access to a variety of mates would have been higher for men than for women (Symons, 1979; Trivers, 1972). Compared with women, then, men may have evolved a stronger desire for sexual variety (Buss & Schmitt, 1993; Ellis & Symons, 1990; Symons, 1979). Because the authors found no previous literature on reasons for friendship dissolution, we adapted an act nomination procedure for securing a list of reasons (Buss & Craik, 1983).