But jeez - just because a guy likes your booty doesn't automatically mean he wants to make you do things you don't want to do. It just means he appreciates your booty!
I'm a curvy girl and even when I was very thin, I had a sizeable booty for a white girl. My last boyfriend endeared himself to me by being the only white guy who ever said he loved my big booty.
This can also be a cultural thing - generally, men of color are more appreciative of a girl with a big booty. Hence, the famous song by Sir Mix-a-Lot;
Guinevere, I'd say the issue here is yours - you've got a man who appreciates your body, and just because you don't like that part, you're not relaxing. Try thinking of yourself as a goddess, and loving all of your body.