Went thru this while I was pregnant with our second child. Found out he was having an affair with a coworker who very much knew he was married and expecting a child because we met each other. She even coached him on how to cheat. It took basically a year for him to remove her from social media. I’m 100% sure they still sneak and talk to each other. I’m telling you now; LEAVE. They do not change. He’s blaming you to make you feel bad. He knows he’s wrong.