Gay and bisexual men engage in a variety of sexual partnerships, but the most common distinction made in HIV research and behavioral surveillance is a binary between "regular" and "casual" partners. The "regular partner" category is often perceived as pertaining to ongoing coupled "boyfriend" relationships, with the literature to date rarely troubling what actually constitutes a "regular partner." Some emerging literature has identified "fuckbuddy" partnerships as a type of regular partnership requiring attention, but it is relatively new and not well understood. Currently, assumptions of the regular partner category do not capture how men perceive and conduct commitment in different sexual partnerships that could also be considered "regular," and the implications this has for HIV prevention. Drawing on in-depth interviews with a sample of 61 Australian gay-identified men, we explore a diversity of partnership types that represent unique ways of enacting commitment. We identify three sexual partnerships: "fuckbuddies," dating, and serial monogamy, each with specific issues for HIV risk and prevention. These partnerships suggest important differences in the way men conceive of and practice intimacy and sex.