Boyfriends insecurities

Okay, so my boyfriend is ridiculously insecure about himself which doesn't make sense because we are a very fit couple and we workout 5 days a week. I've tried so many things to help, I compliment him everyday and tell him how attractive he is. It's gotten to the point where we only have sex once a week and we used to have sex AT LEAST 3 times a week. He calls himself a pig and all of this nonsense. I don't know what else to do, he doesn't want to go talk to someone about it he doesn't think it will help. It all started with his previous relationship which ended two years ago, she was very hurtful with her words. I need advice please!!!!