Most Helpful Girl
All you can do is do you! improve yourself so that when they do break up she is impressed by you.
You do NOT want to take any part in her breakup with this guy.
a) makes you look desperate and annoying, if you make them break up its very unlikely she will go out with you after
b) if she does go out with you - when you guys disagree etc she will resent you
110% nothing is more attractive to a girl than when there ex is doing well and is not hung up on her. Its nice for us to feel there might be a chance but I once had an ex (3 years ago) tell me he'd always love me and any time I wanted him back to call him - its 3 years later we talk every few months but I'd never get back with him because its too easy!
Also never assume that a girls feelings aren't genuine - she may like some guys more than others but that doesn't mean she doesn't care about this guy. Another point when they do break up - don't ever bad mouth her ex... if she bad mouths him to you (alot) then you are the new rebound