I have a fettish or facination with stomach's as well, I don't think it's weird or unhealthy at all. Mine has to do with not only the stomach itself but the waistline as well. I think as with any guys fettishes, it's not the body part itself it's the sexual connection you make with that part. I don't know if that makes sense so let me make the case for my argument;
Yes, even Paris Hilton is hot and I give her props for being a whore and sharing the love, I'd wait in that line;
And even my extremly hot girlfriend has a stomach everyone can love;
Everyone see now why I'm so sex obsessed??