even telling the guy about how bad the boyfriend has been to her

Take this advise from me, if you felt in love with a person and encountered the above situation, the best you can do is listen and advice logically. I know what you're thinking, this is your chance right? That you going to be the perfect one who will never failed or disappoint them. Taking down all the notes, what to and not to do, what they like and dislike, anyway to impress that person and make you make your move. STOP, high chances this aren't going to work. No matter how much they complain about their lover, at the end they'll still be together. Sorry to say, you just a person they wanted to talk or cry to. Even if you confess to them at this kind of time, they might say they still love them, that you're the only person who listen to their cries etc. Ugh...I feel like throwing up now thinking how much of a simp and loser i am many years ago, at the end i gained nothing but depression. That's my advise, and stay away from someone else's gf/bf/wife/husband, don't you ever think about the consequences when get caught?