Dude, I am going through the exact same thing right now, just about. I was dating this girl for over a year, we broke up, I guess it really devistated her, she started dating one of my good friends, and the other night I found myself making out with her. I do have a lot of emotional attachments to her, but mostly because of how physical we were. But still, she was my best friend and I care A LOT about her even now. I hardly talked to her for a month or two after we broke up, but then we started talking again and became "friends" again. Even now when we hang out we'll cuddle when sitting, and even hold hands. And yes, she is dating another guy.
I've decided to try and detach myself from her, as much as I miss being with her and as much as I want her back. Honestly, it's been killing me, and it has made me very stressed out and depressed. She told me that she couldn't leave this guy for me, and even though I'd take her back in a second, I have to respect her decision.
If I keep making out with her and doing other physical things, it's only going to make things more difficult between us. Part of loving someone like I love this girl, is doing what is best for them. I want her to be happy more than anything, even if that's with out me. I really want her friendship so I'm going to work on that, but for now I'm just going to have to distance myself from her. Also, I'm stopping, because I know that my friend that she's dating, even though I hate him now, will be really hurt if he finds out about any of it.
IMPORTANT ADVICE PART:
So to sum it up, if you love her, you'll respect her feelings and decisions no matter what they might be. Please, for her sake, never put her in a situation where you can take from her or do anything to hurt her.
Letting go of someone is damn hard to do, but you just gotta have faith that your going to find another girl.
Good luck man, and be strong.
