idk what to do

my bd was horrible when i was pregnant. we broke up when i was 7 weeks pregnant, barely had any contact and would argue every time we spoke. when our son was born we started talking again and i’ve just found out he slept with 2 other women, he was a virgin when we first started dating. i’m so sad when i go on his social media, he was having the time of his life during our breakup while i was super depressed and pregnant. he’s changed so much and was doing things he always said he would never. i also wanted to become celibate postpartum but he keeps asking for s3x. i love him but i need to love myself more. i don’t want to break up with him as he will not be in our sons life or support him. any advice?