Boyfriend help

My boyfriend dm a girl online that he saw on some Instagram account showing her full ass and twerking and said “hey I saw you on this account and though I would dm you... what’s up😂” I found out and it’s not the first time he has hit up a girl.. idk what to do we have been together for two years and he keeps saying he will never do it again and he will make it up to me but he has said that the last two times he did it! I love him so much and my heart hurts can I have some honest advice please.