Boyfriend comments on other girls instagram

I (28f) found out that my boyfriend (33m) not only comments on other girls posts in instagram, but slides in their dm. His comments are pretty flirting. I confronted him, he says he’s sorry. I cried myself out, I can’t forgive him. Since then i can’t stop thinking about it. What is wrong with me, am I not that attractive to him, am I not enough. This thoughts drive me crazy. What should I do?