Two experiments were carried out to elucidate beliefs about marital fidelity and extramarital sex by examining how the social evaluation of extramarital relationships is affected by three situational factors -- sex of the extramarital actor, the actor's physical attractiveness, and the frequency of the actor's involvement in extramarital affairs (i.e., extramarital experience). Overall, there has been little research on this subject in social psychology, and what findings do exist (Hartnett, Mahoney, & Bernstein, 1977; Vallacher, 1982) have limited general-izability because of the youth of the subjects, contrary definitions of extramarital relationships, and contradictory evidence regarding the double standard.