Despite the implications for human immunodeficiency virus (HIV) prevention and sexual health, little is known about the timing and chronological order of when same-sex male couples disclose their HIV serostatus, establish a sexual agreement, and first engage in condomless anal sex (CAS) in their relationships. Dyadic data from 357 dyads were used to describe when these respective events occurred; whether members of a couple concurred about when the events happened; and the chronological order of these events. For many, disclosure and CAS happened within the first month, whereas an agreement tended to occur much later (if at all). Couples' concordance of when disclosure and agreement formation happened differed by their serostatus, whereas there was little difference by serostatus for CAS. The chronological order of these events revealed interesting patterns and varied substantially. Although two-thirds of partners reported disclosure had occurred first, some reported events happening on the same day. These findings reveal that the first few months in a same-sex male couple's relationship is a critical time period for when information and decisions about sexual health occur. Suggestions are provided for how current and future HIV prevention efforts could assist couples with their sexual health needs.