Cirekiller said:
Part of me wish I could, part of me thinks there too many memories to cherish. That when the pain lessens I'll look back on this as a positive experience.
I hope you don't take this the wrong way, but at times like these sometimes you need an anonymous internet prick to do lay down some cold hard facts.
You've only known this girl a couple of months!
You've slept with her a couple times.
Even though you're not in a 'relationship', you're in the 'honeymoon' phase (the first three months when you meet someone and all the chemistry is there, and you click, and it feels magical, and even the thought of loosing them hurts).
This girl never mentioned she had a boyfriend, you had to find that out from one of her friends.
She didn't lie to you, but she hasn't been entirely open and honest either.
She doesn't know what she wants, and although I'm sure she really likes you, if she wanted you that badly she'd have split up with her bf before sleeping with you (and from the sounds of it leading you on so that you'd put the moves on her).
She has all of these qualities that you seem to love, and there's all this chemistry and spark between you at the moment, but long-term do you want to be with someone that displays the above qualities? (cagey about telling the truth, unsure of what she wants, willing to play with peoples feelings to 'test the waters' regardless of who else may get hurt).
For your own good bail out now.
Bail out before knowing her for three months becomes knowing her for six months, a year, two years. The longer you let this game go on the more it's likely to hurt when it, very possibly, blows up in your face.
Unless you're one of those people that is willing to put up with some of the above character traits in a partner (and I'm sure there are probably some people out there like this), be smart and call it a day before you get in any deeper.
I'd advice you don't sleep with her again, and stop hanging out with her one-on-one. If you must keep her as a friend limit it to times when you're all out with other mutual friends...
Unless you're just looking for some pussy to fuck every now an then, you don't care about wrecking some other guys relationship, and you're not the type to catch feelings easily (which it doesn't seem like from what you've said so far), no good can come of this situation as it stands currently.