Got cheated on

My boyfriend had been cheating on me for two years now he was on and off with a girl he claimed was his “best friend” it bothered me so much from the start because i had such a weird feeling about it but i tried not being one of those girls that makes their boyfriend unfriend their past friends so i just let them continue to be friends. I’d occasionally would catch him and her sending each other hearts and their texts to me looked like they were flirting and i talked to him about it and asked for him to stop sending her things like that. Like you know that saying “don’t do good things that seem wrong” it’s exactly what i told him but he started yelling at me and saying i was controlling and that i didn’t have any right to tell him who he could and couldn’t be friends with so i just stopped and said okay because i didn’t want to be that girl. Time passed and i caught them planning to have sex and that’s when i broke up with him i knew i wasn’t wrong my gut feeling told me i was right and i turned out to be right it was so disappointing to see those messages and pictures it broke my heart and this was only a year in right. We broke up we took time apart and he came back trying to fix things and you know like most girls i took him back he promised to never do it again blah blah blah he was going to block her y’all know how this goes. After a while we were good happy no arguments she or so i thought was out of his life. Then i get a message from him “she made a new IG and i let her follow me but I’m not going to follow her back” like how stupid do i look right. I told him block her or please just leave me alone I’m not going through it again and so he blocked her and we moved on and then later again i catch him texting her but turned out she was saved as a code name so i wouldn’t know but i found out because again my gut feeling told me something was up and i went behind his back and went on his phone. I pretended i didn’t know for 2 weeks to see how long this would carry on for he didn’t stop he kept messaging her and making plans with her all the things he lacked with me his girlfriend he provided for her love affection attention empathy the willingness to try it broke my heart. I didn’t say a word for those two weeks and then i check my Instagram and the girl had dm me screenshots of their conversation and i confronted my boyfriend and he had supper his phone clean. What sucks the most is I’m pregnant he doesn’t know should he even ? I don’t know what to do he’s trying to fix things with me but it’s been 2 years with the same bs same arguments same constant shitty feeling i feel like it’s not a proper environment for a child maybe split custody and separate houses is the best for the child but then again it’s never what u pictured how I’d start a family alone scared it sucks i have all these mixed feelings and no one to talk to be cause he was always allowed to have friends and i had to cut every single person out of my life for him.