Same exact situation with me. We had been dating just under a year, she was a great girl, I really liked having her in my life, it was really convenient, but at the end of the day, I knew deep down that I wasn't satisfied with the relationship and her, and that I wanted something better. I was attracted to her, and we connected very well, but something was missing. I ended up telling her that we needed a break and then I started dating other girls and soon got into a relationship with one. The new girl I started dating made me realize why I wasn't satisfied in my previous relationship. It was worth it. Recently the first girl contacted me again and we ended up hanging out a few times, and seeing her now makes me wish I would have ended it a lot sooner.
When you were talking about how you were distant and then she started pulling away, and then your interest suddenly peaked again, it reminded me of exactly what it was like for me too. I think that our lives were so intertwined that it was really hard to actually let her go, but in the long run it was better because this way we'll both be happier. She can find someone who really wants to be with her, and I can find someone I really want to be with. It's almost like we develop a oneitis for girls like this when we think they're going to go because they worked so hard to keep us that it was really nice and convenient to have them in our lives. But looking at the long term picture, if I'm not completely happy with the girl I'm dating now, it's just going to get worse as time goes on. I like to be in relationships with girls who I can truly respect and who I feel like I can't do better than.
Anyway, it was hard to break up with her, but I did, and I ended up finding A TON of new girls that I'm much happier with. It's hard to let her go, but I think that's what you should do. Also, it's no surprise that she's still sexual with you, because it's comfortable and convenient. Once a new guy comes into the picture though, that'll be over. If you start moving on and she can see that, she'll probably start working to get you back. But at this point your relationship will probably never be the same again. She's moving on, it might be good for a little bit, but long term those same problems are going to come back, and she isn't going to work as hard at it because now she knows she's okay without you.
This is like a novel. Cliff notes: I'd move on. If you weren't satisfied before, you won't be now. There are so many pretty girls out there. Go find one that you don't get tired of and that you don't feel like you can do better than.
