thoughts on my problem.

Here is some context me and my boyfriend are both 20 years old we met in middle school but started talking right after graduation so about 2 years ago I have a 3.5-year-old son that I had previously with an abusive ex, and he knew about him and decided to still be with me. We also had a little bump in the road in January he said he wasn't happy with our lives right now and about 10 hours later he realized that he made a mistake and we talked and said we would be better this time but that whole month you could just see that he was tired and didn't want to be together anymore. Basically, me and my boyfriend broke up in February because he said he wasn't happy and that he didn't see us working out and that he no longer wanted to be in a relationship. With that being said we said we could still be friends which only lasted a week because he started talking to this girl he was previously talking to when we were together, and he constantly told me not to worry about her. They never got together when we were together, but he did start seeing her the day we broke up and then came back to me a week later telling me he wanted to work things out and sat outside of my house with me and cried that he loved me, but he liked her. He ignored her for 3 hours that night just to talk to me and basically tell me she was just a void because he loved me still. Fast forward another week he stops talking to me all together and he's going out with her nearly every day and I'm just stuck trying to figure out what I'm going to do now. So, I started working on myself and I was doing pretty well, and I was slowly getting happy, but I constantly missed him and knew that I still loved him more than anyone I'll ever meet. 2 months go by of not talking and he randomly texts me asking how I am, and I was trying to be distant and shut it down because I didn't know what he wanted or if he was just wanting to know if I was okay. I ended up telling him I was sorry for being rude I was just not expecting him to text me since I assumed he didn't care about me anymore. He kept saying he consistently thought about me, and he just wanted us to be friends because he couldn't just drop me and not talk to me it wasn't normal for him, he said he wanted to be able to ask me how my day was and still talk to me like I was still important to him. It confused me because I thought maybe he is just messing with me or maybe she didn't want to be with him, so he came back because it was easier. We decided to be friends and hangout frequently so one Friday we decided to go out for a drive and just kind of hangout not necessarily talk but just be each ithers company. It was nice he looked different from the last time I saw him I kept having to look out the window because I kept crying. He kept looking at me and just kind of stared at me he didn't really smile or anything unless I did, I was a little uncomfortable, but I didn't want it to end just because I still loved him, and I could honestly stare at him forever. he kept looking at me like he wanted to say something, but I just assumed it was because he wanted to go home so I just said I was tired and that I had work in the morning but it kind of made him look even more uncomfortable. the ride home was pretty silent, but I dropped him off and we sat in front of his house for a while he kept asking me to get closer to him because I was standing a couple feet away from him, so I did, and we hugged I was happy. He still kept looking at me like he wanted to say something but kept telling me he didn't know what to say or how to say it, someone came outside though and I kind of just jumped from him and we just decided to talk later, and I just went home. we continued to hangout the next few days and I was surprised he wanted to hangout so much because when we were together, he didn't really want to hangout everyday just because he knew there would always be a next time. We did both come to an agreement that we would be friends, and this would be our make it or break it we'd either realize we needed to not see each other anymore because it was too hard or that we should try and get back together but we should restart. It was hard to say that just because we had no idea what was going to happen, we decided to do it anyway but one night I got really upset about something and drove out somewhere and got lost and he called me and told me that I should've came to him before I left so I wouldn't be alone, and I said we've hung out the last 5 nights so I assumed he didn't want to see me again. he started telling me that I'm not just some random person to him and that he could never get tired of me and that he cared a lot about me and that I needed to come back and get him, so I wasn't alone. We ended up going to this spot and we talked, and he said that we probably don't want the same things and that this could get difficult but that we needed to get this out of the way so I thought that he really did just want to be friends and so I kind of said yea we probably do want the same thing you just think too much about this but of course I wanted to be with him I just didn't want him to think that because that's what hurt us the first time but then he said that he still loved me and wanted to take this slow because he can't just not have me in his life anymore and that he understands if that's not what I want it's just what he'd like to continue to do. I immediately told him I assumed he didn't want to get back together at all, and he looked at me and asked if that's what I wanted and I told him that I'd like to be with him again just not right now because I can't trust him. He agreed and then told me he wanted to keep seeing me just in case I realized that I didn't want to be with him and that he didn't want the last time he saw me to be a bad memory or that he didn't get to see me enough and that he could remember it this time. That made me absolutely bawl my eyes out and he hugged and kissed me and told me he was sorry about what he did but that he doesn't take it back because we both accomplished things we wouldn't have been able to do if we were still together which I understood but didn't like at the same time. It's been about 2 weeks ago since then and he finally came over to my house it felt weird, but I was able to lay down with him, now this is where I feel dumb. I couldn't fall asleep for the life of me he passed out like 15 minutes into us laying there and remember the girl I was talking about in the beginning I couldn't stop thinking of why they stopped talking so I took his phone being the dumbass I am I went through all of the messages. this is where I want to understand now they would go to car meets regularly which I knew about and I knew she was there, and I didn't care but she was consistently telling him that I was not what he wanted and that he could do better and talking shit about me which I honestly don't care. but he listened and told her everything which I didn't like and then started seeing her every day and they got closer but shed still shit talk me and he would shut it down almost immediately she obviously hated it but she kept doing it she would tell him that she could do things to get his mind off of it but he clearly just wanted her there as a friend because he kept saying no she would call him "my love" and he wouldn't even talk about it she constantly asked him how he was feeling and when they could see each other next but he kept saying he was too busy after a while and then she just stopped texting and that is when he kept saying like when are you free or how have you been and if she as okay and just checking on her but she was already gone by that time so the last time he texted her was 2 days before he texted me asking me how I was doing which idk how I feel about that honestly I really don't I know that they aren't speaking anymore but I don't know how to feel it kind of made me sick to my stomach and I don't know how to confront him about it so if anyone could help me I'd be really appreciated on some advice.