It's taken me a while to post here but what the hell, we're trying to reach 200,000 posts.

I don't particularly like to be fingered because I was molested and that's one of the things that was done to me. However, this experience did not make me frigid or lesbian. I love sex and I love cock (well, one cock in particular...) but I just have negative associations with being fingered.
Also, I'm certainly not implying that your girlfriend dislikes being fingered because she was molested. I'm merely stating my own personal reasons for disliking it.