I think hypo's got it. Maybe the woman talking slept with this guy, then he mentioned he's still with Liz--but don't worry, because Liz won't freak out over some little fling. So the woman called a friend to complain about the guy, and her friend commiserated over how much it sucks that the guy is still with Liz, so the woman then had to clarify what was bothering her.... Or maybe I think too much.