I can't get over a woman who has a boyfriend because she treats me like she's into me...what do I do? Wait?

Just go for it. If she does anything with you she isn't into the guy. I mean, do you know the guy? Who cares if you hurt him. If you're going for girls at least have the mentality of a guy. Not to mention a lot of guys won't care if their girlfriend screws around with girls. So yeah, go for it. If she stays in a relationship then be around when it ends. Don't restrain yourself for the sake of some nameless guy.