UPDATE: Broken Hearted and 31 weeks pregnant bad combination

So the other night me and my boyfriend where laying in the bed watching tv. We both got hungry and he decided to go downstairs to warm up some food for us. When he left his phone had went off and I thought it was a call because his mother had been calling him maybe 20min before. Well it was an Instagram message from a women. I couldn't see what he put because sneaky as he is, he deleted it. But what I saw from her was enough to make me go 0 too 100 ! 
So I waited until he came upstairs to try and calm myself down and I confronted him about the message. First he said he wasn't sure why she sent him that message, I walked away and called it bullshit because that's what it was and he was caught red handed. We got in a big argument so I slept in the other room. The next day he left for work. I couldn't let it go and I knew he wasn't going to be real with me so I decided to send the women a message myself to ask her what the relationship was between her and my boyfriend. I didn't come off disrespectful but women to women. Well she basically told me that they had knew each other in high school and they would basicallly keep contact with each other off and on for the last couple of years. And recently they reconnect. She said she knew about me and knew that I was pregnant but he told her that I had left and he was upset( which I did at the time because of drama in our home with his father) then she told me they had sex. So basically they linked up for a couple hours. So when I went to him telling him what she told me he claimed she was lying and that she hit him up first on Instagram and that he may have done a little innocent flirting with her while drunk but that was it. Well she ended up sending me proof that he had her here in our home while I was away. She took a picture of him passed out in our bed. When I showed him the proof he claimed she was crazy and he didn't know how she got that picture from. 😑  what I can't understand for the life of me is why lie ? Especially when I have proof ? He still couldn't man up and admit he was wrong. So now my heart is broken and I can't trust this man. I live with him in NY and all my family are in va. I don't really want to stay here in the same house especially since he had someone else here ain't no telling who else he had in here. I'm trying to keep it together. Tomorrow my plan, when he goes to work I am going to charge his card and book a flight out of here for me and my 3 year old back home to va. This man put me through hell and I can't take it anymore. Somebody pray for me
UPDATE: thanks everyone for your love and encouragement. I will be out of here the first thing smoking. I'm trying to remain calm but it's killing me mentally. All I keep doing is praying. He's been giving me my space in the house but keeps saying " I love you" I turn my back towards him every time because that don't mean a thing to me plus he turned his back on me when he betrayed me. I will update you all when I am gone. Please pray for me once again. Me and my 3 year old will be leaving and I feel bad that I moved him here in the first place. He doesn't know what's going on.
UPDATE#2: me and my son just made it back home with my family, I feel so much better but he freaked out when he seen that I charged his card for the flight ticket. He cursed me out and said I would be arrested if I got on the plane and I said to him "well I guess I will get arrested" then he swore up and down that I fucked up our unborn and my 3 year old future. And I informed him he fucked up by cheating on me and breaking up our family. Nothing else to say to him right now. I'm just praying god will ease my mind because it is all over the place. Thanks again everyone for your kind words. I really appreciate it ❤️
UPDATE#3: Once again I want to thank everyone who sent there love and best wishes to me and my son. For those who have asked my son who is 3 is doing great. He is happier to be back home around family. I feel bad that I had to take him out of school because he was in Headstart in NY. I called his school but I couldn't get an answer so I am going to try again before 4pm to let them know he won't be returning. I feel kind of embarrassed because I don't want to tell them exactly why he won't be returning to school but I had to do what's best for us. I also have to focus on getting my insurance switched to Va now that I am here and find a doctor. My  due date is approaching in June and the sad thing is all of the things I gotten for the baby so far I had to leave behind. So I don't have anything right now but I am not going to worry about that because I know god will provide and make a way if I continue to trust him. My now ex boyfriend sent me a text message last night saying that the baby will not be staying in va. So I guess that's his way of letting me know he will be fighting me in court for custody after he is born and I told him to bring it on !