I'm pregnant and he's cheating

I'm 4 months, and I just found out this morning that SO is cheating. He's taking dick pictures and sending them to other women.
I surprisingly have not cried.. I'm just disgusted with him. How can a man have the balls to do this while his partner is carrying his child?
I have no idea what to do. I'm thinking about kicking him out, or myself moving back in with my mom. I'm just done with the bullcrap.
This isn't the first time he's cheated, and honestly I was very stupid and naive to believe that he would actually change!