Infidelity during pregnancy

Hello ladies,

I need calming, soothing, words of wisdom right now. Okay, so I found out that my boyfriend has been cheating on me. Jun 17 is when I had my first ultrasound, he wasn't able to make, so I called and told him what we were having. Would you believe while I was telling him, he told me he has to call me back, he's driving , and the police are out heavy. Honestly, that pissed me off, I didn't call him back, he couldn't call me because my phone wasn't working. Three weeks later, I decided to text him to let him know that his daughter is fine. He was excited, but upset that he wasn't able to talk to me. He called one of my good friends, but also a mutual friend, to see if she spoken to me, but neither did she. He kept asking if I loved him literally everyday, and told me that I need to show my affection much more. I agreed, so after that, I thought everything was fine. Until I asked him if he was sleeping with anybody, he told me yes. He said not every night. He also told me to not worry, because he and I were good. That broke my heart to know that he has been having sex with another woman. He kept hugging on me, kissing me, as if what he told me was normal. He told me that I've been sleeping with someone else, but I never cheated. He and I have been on and off going on 4 years, and for him to betray me in that manner really hurts me. So I tells him that I'm not dealing with that, I don't deserve it. I told him to leave me be until I get myself together. I told him that I don't want anything to do with him. After that, I go on Facebook and see where she tagged in a picture. It's clear to what has been going on with then two. She's talking about how she loves him, and he's professing his love for her back. That ripped my heart out. I just cried, it's pain that you can't get rid of. I don't know why he would betray me like this. I don't want to become bitter , I don't want to hate him. I just need words of wisdom at this point. My best friend words wasn't good enough, so hopefully y'all can help me with soothing words.

Thanks !