Dating friend's ex

Okay, so he's not her ex REALLY, but I thought that description might get more views and I need advice! I am absolutely infatuated with this amazing guy but he went on a couple of dates with my friend. She now has a boyfriend and is not into him anymore, and I can't understand why. He's so amazing, has similar interests as me, is very cute, and just amazes me overall and I'm only recently starting to hang out with him. Going on a date with him would be a dream come true, but don't think it will ever happen because I've been "her friend" up until recently and I'm not sure if I can, or should, try to change that. What should I do?