Just a thought...

I may get flamed for this, but very often women (and men as well) don't like to be alone. In other words they will stay in a less than satisfying relationship until something better comes along just to have the companionship (and sex).

If she's kissing you and stuff either she's not a very loyal woman or she's not happy with her current situation and is looking for something new and better.

I had a girl Saturday night in a club slip me her phone number and gave me a big kiss (tounge and all) three feet behind her boyfriends back saying 'call me Sunday night.'

I did call her and left a message 'thanks for the interest and I find you attractive and all but we can only be buddies as you have a boyfriend.' Probably would have persued it a bit if the guy hadn't been twice my size and looked like a bad-ass. LOL.