Most Helpful Guy
" in the past he played her a lot and cheated on her"
"the reason why was because he felt alone and had trouble paying for rent"
"basically he was used to this girl"
so just to be clear... you're attracted to a guy who cheats on his girlfriends, uses them so he can afford rent or hangs around them just so he isn't lonely?
Boy he sounds like a real catch
I'd say move on. Find a better guy. If this guy you are "head over heels" comes up one day and is free and you are too then you can see what's what but while he's with that other girl you might as well just leave it be and frankly I think you should really think what makes this guy (aside from being attractive) such a great person