Not sure anymore

My boyfriend and I have our ups and downs, and right now I'm just not sure what to do. He is in school and takes adderall when he does he is an ass. I hate that stuff, so he finishedup the   semester last week and now is making smart comments about being bitchy and lazy. I am 20 weeks pregnant and have 3 kids already. I'm always tired but I fight it just to clean or to do things with the kids. And last night he started taking about messing with other girls. I'm just not sure. Lately I can feel my love for him being sucked right out of me. Like my ex husband was like that and I'm heading in the same direction and I can't do that.