Some men really go for large breasts. I know that when I was in my 20's, bigger breasts were what I preferred. But now, I'm not concerned about breast size at all, but rather the aesthetic quality (ie: form and shape). Like, I find those Baywatch blondes' breasts too big and blobby.
I wonder about your bf, though. Is he dating your breasts, or you? I find it disturbing. Some guys aren't as lucky as he is to have you.
If he gets out of line, tell him you're putting up with his penis size, so why won't he put up with your beautiful c's?