Thanks for the replies.

@hamster - Yes, I have thought the same thing. It's difficult to pull away from physical contact with her without giving her a reason. She just thinks I'm mad at her or something. Should I tell her that is why I am not interested in physical contact? It seems like that would make it seem like manipulation or put pressure on her if she knows why. In general, I have been too submissive to her, I think. I eventually give in to what she wants too easily. It's hard to feel an intense desire for something (someone) you know you already have. Should I sleep on the couch to avoid the inevitable cuddling at night as well?

@Camel - We live together in a studio apartment so we are right next to each other any time we are both home. It's hard to get much separation between us. I go out with my friends sometimes and also have hobbies and interests outside the apartment. She doesn't. I agree some separation might be good, but we occupy a very close space. I'm trying the physical separation, not touching her, but eventually I'm going to have to tell her why. Today she kept trying to hold my hand and I wouldn't do it, so she asks me why and what's wrong but I don't know how to answer that.