Just now finding out a lot of little secrets about my husband ...

Idk what to think I'm seeing his Facebook and before marrying me and meeting me he had like,3-4 girlfriends at once. Chronic Cheater claimed to be in love with some women, and there's girls he claimed to be friends with that he actually had feelings for. Got me right in the trust. Idk what to do and when I bring it up he tells me I'm his wife none of them were his wife so it's different... can a man just stop being a player douchebag and get married and be suddenly changed ?!