Maybe! but that's another story.
Just imagine for a minute that you wanted to entice a young guy into sex. Would it be hard to do as a woman? This guy has been faithful for years or whatever and suddenly cheats with his girlfriends roommate while they're drunk. It just sounds a bit suspicious to me, sort of like someone taking advantage to steal a boyfriend sort of thing.
I just don't see the logic in ending a long-term relationship overnight because some skanky roommate decided to fuck with your life (and boyfriend). She's obviously looking for a reaction when she confronts and admits it knowing how big a deal this is.