Advice ??

Recently I found out my bf has been cheating. He’s done it a few times here and there, nothing physical but I always find messages like “you’re so bad” “you’re so beautiful” and heart eyes on girls pics... so we decided to work on things and both agreed on deleting our social media accounts and the apps from our phones in order to work on the relationship. A couple nights ago I had a weird gut feeling like something was wrong and went through his phone to find out he signs in to Snapchat everyday and of course I found several messages with lots of girls including a girl he used to talk to for a year but never really had the title of a “relationship”. Anyways I read a lot of things I couldn’t believe. We broke up a couple times before and I found messages from when we broke up and he told another girl that I was “dick whipped” and sent her the screenshot of things I said to him. Which I felt wasn’t any of her business. I also found that when he got his new car he sent his ex the picture right away, kind of like wanting to share special moments with someone you care about. At least that’s what it felt like to me. I have tried breaking up with him for the past 3 days and I can’t seem to do it. I know I shouldn’t be with him if he has cheated so many times. I can’t trust him or even believe him when he says he loves me. But I have pointed so many things out to him about how he accused me of cheating but he’s the one who has been cheating for months. He doesn’t ever really say anything and it kind of bothers me. He knows he’s wrong but he never knows what to say. I’m scared it’ll happen again and again but he swears up and down he will never do it again. Btw, he says he’s cheated because he feels as though I do it to him, so when he finds out that I have (which I haven’t) he would feel better and get over me quicker. He dated someone for two years and she cheated the entire relationship so he has trust issues but now I feel like I’m paying for something I didn’t do. He wants to work on this but I’m not sure I can trust him, or do people ever really change??? I don’t know what to do and I need help!