Marital sex has been an unaddressed component of sexual risk. This article explores marital sex and its link to men's extramarital sexual behavior in 3 economically marginal communities in Mumbai, India. Using in-depth interviews with women, men, and couples, qualitative results are presented on first night experiences, ability of women to refuse their husbands' demands for sex, sexual communication, and sexual pleasure associated with marital sex. Using regression analysis of survey data for 260 couples, the quantitative results indicate that greater sexual satisfaction for both men and women is significantly related to men's lesser involvement in extramarital sex. These results provide a basis for a couples' intervention effort that can yield greater marital and sexual communication and reduction in sexual risk.