Using a probability sample of 912 Latino gay and bisexual men at bars in 3 U.S. cities (Los Angeles, Miami, New York), this study examines how participation in difficult sexual situations with interpersonal (e.g., wanting to please partner) and circumstantial constraints (e.g., sex in partner's home) may explain associations between dimensions of intimate partner violence (IPV) and HIV sexual risk behavior (unprotected anal intercourse with nonmonogamous partner). Findings suggest that all IPV types contribute to greater participation in sexual situations with circumstantial constraints, and that psychological and sexual IPV are also associated with higher likelihood of unprotected receptive anal intercourse with a nonmonogamous partner. Circumstantial constraints fully mediate the difference attributable to psychological IPV and partially mediate the difference attributable to sexual IPV. Intimacy concerns were unrelated to either IPV or HIV risk behavior. Results suggest HIV prevention and research should investigate immediate circumstances of the sexual encounter that may make engaging in HIV sexual risk behavior more likely.