One of my guy friends seems to really be interested in me. We've hung out on multiple occasions and every time we hang out he takes things a step further (for example, the first time we hung out he didn't ever touch me, just sat close to me, and now he's letting his hands slide up my shirt). It seems like he's taking his time to get to know me and I like him a lot, but the problem is that he has a girlfriend! The other night he told me that they both keep things from each other and it immediately turned me off. I don't want to cut him off completely because he's a great friend to me but at the same time I don't want to be the other girl. He hasn't made a move on me (apart from having his hands around my waist) but my friends are saying that it's bound to happen soon. I'm not comfortable with having an affair, yet my friends think that that's the only way I'd ever be able to be with him. I was hoping that if he liked me, he'd actually break up with his girlfriend. What should I do?