There is nothing wrong at all with being interested in sex, many people are. Just gotta be careful with who you interact with. But honestly, it is awful that your boyfriend acts disgusted with your breasts. :/ I would feel completely terrible knowing that my boyrfriend hated a certain part of me, in fact, I doubt I would put up with it.
No offense, but that's completely disgusting if he hates your breasts, and if he only loves you if he has sex with you... Seriously, break up with him. If not, kill him.
Nothing wrong with sex. Just be safe! But if your boyfriend is actually 'disgusted' with your breasts and hates them then you should fucking dump him. If he was good for you he would love every part of you and your body. I'm a B and I've never had any complaints...