Hard to trust him again

I need advice . My boyfriend and I been dating for about 3 months now when I first met him I thought he was the one . We moved pretty fast on our relationship, he’s 25 and has 2 little girls which he only saw during mornings he didn’t have the girls for much time . He was also married before me , he was honest with me from the start . I told him it didn’t bother me at all because honestly I don’t like to judge people off their past . Everything was going great I wasn’t worried off his ex wife because she would only talk to him about the kids . He had her phone number and It didn’t bother me because I understood that he had to have some type of contact with him over his daughters. But I did let him know I didn’t want to deal with his ex wife anything to do with her at all that’s none of my business. He assured me that she wasn’t going to give us any problems . I met his daughters, I met his family everything was great or so I thought . One night he told me he wanted to see late at night like around 11pm I had just gotten off of work and I was exhausted, I told him I couldn’t it was late and I wanted to rest . He got pretty upset about it he told me was having doubts about us because we couldn’t see each other any time . I was heartbroken just the fact that he was having doubts . I told him if he didn’t want to be with me to let me know I wasn’t going to beg him but I don’t want to be playing any games . He said he wanted to see me because he was having bad thoughts and he needed me I told him I couldn’t . We argued for a bit then he said it was fine . We said goodnight and everything was good I went to sleep . As soon as I woke up because I had work early in the morning I woke up with a lot of messages on my phone and missed calls . One of the messages was from his ex wife on fb she sent me screenshots of what he sent her . He pretty much told her he missed her and he was depressed after they divorced and he told her he didn’t want to do the divorce but he was forced to . He told her how much he loved her and everything reminded of her and how he tried to be happy but he couldn’t . He said he would do anything to get his family back and he would do the marriage therapy thing. Etc he also sent her a inappropriate picture of him . When I saw those screenshots I broke down I didn’t get mad at her because she didn’t do anything wrong. I thanked her for telling me about it and she said he told her that he broke up with me last night . She told him she didn’t want to be with him and that’s when he said he wasn’t being serious.

I confronted him about it of course and he told me a big lie he said he was at the hospital because he wasn’t feeling good and that he was unconscious. That the hospital called his emergency contact which was his ex wife . She got there and grabbed his phone and texted all those things to her . He kept telling me that I didn’t know what to believe so I forgave him and believed what he said . He assured me that she lied because she still wanted him, he told me to block her on everything I told him I would but I didn’t . Later on I couldn’t trust me it was a gut feeling that I knew something wasn’t right , I asked him for the papers they give you at the hospital he said he didn’t have them . I had to force him to tell me the truth he said he wasn’t at the hospital. He said That the messages wasn’t his though that she lied . I was mad and I told him I would never trust him for lying to me . He apologized and said he wasn’t going to make any mistakes and that he loved me . I forgave him and I told him I’ll give him another chance . Time passed I had to go to LA for a week and I told him he better be good and not to do shit behind my back he said he wouldn’t keep in mind I had his location and he had mine . So I would see where he was at . 2 days in LA we were texting and he said he was feeling bad about his grandma because she was sick . He told me had to go to the park to get stuff off his mind . He got home and we texted but he would take forever to text back and I had a bad feeling about it . He assured me he wasn’t doing anything bad . I fell asleep I woke up next morning with a bunch of messages again . His ex texted me again telling me she was with him last night and they had sex . I confronted him about it of course he told he did see her last night but only to talk about the kids . She sent me screenshots of him telling her to come up by his house . He said they only talked about his kids and that he only did it for that . She assured me that they did have sex . He told me they didn’t have any type of contact but only a kiss on the cheek and a hug . I was heartbroken I told him I was done . He told me he would do anything for me . To give him a last chance he blocked her on his phone and everything. He got my name tatted . He was begging me to stay with him , he pretty much ruined my trip . Till this day I can’t trust him I beg him to tell me the truth if he had sex with her and he said no . Till now he won’t tell me . He tells me if he really didn’t love me he would have never introduced me to his daughters or his family. So far I’m doing good with him but there’s days when the memories hit me and it hurts he tells me to move on and start over . But I can’t trust him I need the truth. I don’t know what to do he proposed to me and we going to Vegas next month .i need advice

This is what he said to me right now