An ambiguous incident seven years ago that is only known because she confessed? In the first place, it sounds like the issue is alcohol, not infidelity--people of all genders who get drunk are prone to doing shit like that. If I where in the husband's place, what I'd be more pissed about is her unburdening her conscience at my (i.e. his) expense. That's what that kind of confession is really about. Coming to him the next day might be an honest confession. Bringing it up seven years later is just passive aggressive. He should consider divorce, but for the original crime, but for the confession.