My friend has been dating a girl off and on for approximately six months. They've broken up several times, and he's cheated on her multiple times. I live with this friend. Last night, they finally broke it off for good. As it's been a cycle of breakups, I'm guessing that the emotional impact isn't quite as strong as it would be under normal circumstances. I am really attracted to this girl, and am contemplating asking her out. Clearly, I'm going to wait several weeks to even mention anything to her, and will run it past my friend before doing so, but is there anything else I should be doing? Any suggestions from someone who has gone through this situation before?