heytheresandy, he sounds clueless. Reminds me of my ex husband who didn't like a few of my body features (I show too much gum when I smile, nipples too pale...you get the idea) He'd say whatever he felt like about me while I constantly reassuring about his small d*ck. To this day, I regret not being more assertive about it all. Anyway, I don't know how to approach the lack of compliments....but I do have some ideas approaching his insults.
1. ask him if he's ever heard the adage "if you can't say anything nice, don't say anything at all". If he has heard it, tell him to live by it.
2. if he says something about a breakout say "why do you feel the need to comment on this". Seriously: press him to find out what he gets out of it!!
3. or "why are you so unkind?"
4. if he says rude things when you're about to have sex, get dressed and walk away.
5. Regarding the size of your bum, I'd be inclined to get stuck into him about that one. Exercise really isn't going to give you a big bum. If anything, the toning may even make it smaller. I'd be retuning a comment such as "my body is the way it is. If you want a big bum, then go and find a girl who's got one. But shut the F up about my bum"
6. if he says he's just messing about, ask him how he'd feel if you made fun of his lack of abs/small penis/insert whatever he's insecure about.
Having given you all these comments, I suspect that even if you can stop him from making the negative comments, you'll still know that he's thinking them. I mean, he's given you far too much insight into his brain. And that brain is thoughtless.
It's OK to end a relationship over something like this. I mean, can you imagine being MARRIED to a man who's like this? What thoughtless things may he say to your teenage daughters when they are at their most insecure and vulnerable? I mentioned my ex-h in the start of this. To be honest, it took a different man with a different attitude to make me feel more positive about my body again. Now that I'm older and wiser, I wouldn't put up with these types of comments for a moment....but it's not so easy to know the boundaries when you're 20.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.