I did read your post and I know you said you can't do anything to change the way you feel about fat girls. I thought that was crap. The mind is a very powerful thing. If you convince yourself that you can never change, then no, you won't. The line goes something like "whether you think you can or you think you can not, you are right." But then I was thinking about it more and maybe you do have the power to change things, but why bother. It's not like your preferences are ridiculous. I wouldn't want that last girl either. As long as the third girl isn't too much for you, then I don't see anything wrong with the size you like girls to be. If you had said even the third girl was too big, then I think maybe you'd have unrealistic hopes. Most girls are closer to the 3rd and 4th girls than the first two. Then again, there are plenty of skinny girls out there looking for a nice guy.
There's nothing wrong with liking your girls a little on the slim side. I like my guys a little on the meaty side. I dated a guy before who was real sweet to me, but he was the same height as me and underweighed me. He was in good shape and all and I'm a little pudgy. In any case, I knew it would never work out because he was too thin. I like a beer belly on my man. I like them to be taller than me. I like to feel safe and protected when my man wraps his arms around me. I like to feel little compared to my guy. (Wilson is all of these things.)
Anyhow, we all have our set of physical preferences that we look for in another person. No big deal. You don't need to change the type of girls you look for, just keep looking. Look in different places maybe. I don't know. I stumbled upon my guy, pure luck. Keep trying.
I have a friend... she's going to the gym, she'll be thin soon. Well, not that she's fat now, but she'll be thin for you soon. :-)
1212 Out.