What to do about these "daddy issues"?

First things first, background. I'm a senior in high school, currently. I was sexually abused by my father from the time I was 2 to the time I was 7. I've forgiven him mostly, but things are still off between us. It's more like an ex-boyfriend I've become friends with than parent-child. Neither of us even knows how to act like real father and daughter.

On a side note, I'm a lesbian, and I have a girlfriend. This is _not_ the problem. I've been with my girl for almost year and a half, and for the most part, we're just fine together, in both our sex life and our relationship. So, at least my ability to do that wasn't too horribly damaged.

Now, for the problem. There's a teacher at my school, I'll call him Mr. R. I've been in his classes for two years, first with drafting and then with metal shop. He's just a kind man, and really caring. Over the time I've been in his classes, which is longer than most girls, I feel like he's come to be like a father to me in a cleaner, healthier way. This kind of scares me, since I didn't have any good luck with father figures in the past.

See, I don't really know what's okay or not in these situations. I mean, sometimes he gives me endearing nicknames, like dear, when he's asking me what I need for projects and such, and he just tends to be looking out for me. I get the feeling that I'm special for him because I've been in his classes so long. None of this feels like it's a breach of ethics or anything, but, again, I have a highly skewed perspective.

And also, what's okay for me to do? I was talking over this with my girlfriend, and she liked the idea of me having a father figure, but when I asked her if I should tell him he's like a dad to me, she said definitely not, and I felt stupid for not knowing that that's not okay. So, if that's not okay, what _am_ I supposed to do? I'd really appreciate any advice at all. I'm flying totally blind here. Thanks!