Break up or stay?

I need help. Me and my boyfriend have been together for almost 3 years. We have an almost 1 year old. He has been disloyal in the beginning before we found out I was pregnant. Then recently in the last few months I have found 4 pictures of his penis that I have never received. He lashed out on me everytime I confronted him saying I’m like his mother and control him and it just is really bugging me. He insists he’s not cheating and he’s been so nice but come on. I feel like he’s kissing my ass. Please help. I don’t know whether to follow my gut and leave and put this to rest. Or really try and work this out. I’m trying really hard to put the past in the past but this is a recurring issue I can’t handle anymore.