bro, if u really like her than tell her that u still like her. dont worry about tellin her the bad things about d cuz if she still likes u(sounds like she does) then that shit wont matter anyways. shit'll probably work out for ya. but if she does keep goin out with him then go to him and tell him that he better not just fuck and duck her and he better treat her as nice as u treat his mom. lmao scratch the last part i couldnt resist. but yea tell him to treat her nice... hope shit works out