I hate how my belly moves during sex

My boyfriend and I just started having sex, I was a virgin before him and I'm noticing I'm more uncomfortable with my body than before. I workout a lot, but not as much as I used to, due to a lot of back pain within the last year. Anyways, I notice when we are having sex I don't like it when he's in a position where he sees my stomach and it's rolls and I have a hard time facing him...