Feeling guilty

My boyfriend and I are going through a very rough time right now. I made so many mistakes in our relationship. I didn’t cheat but I wasn’t loyal and I constantly confess which drained him. We eventually came back from it, I learned how to move on and stop confessing, and I improved myself so I could be a better girlfriend. Lately I’ve been feeling very insecure and I’ve had this huge fear that he’s cheating on me. I’m constantly brining up things from the past that he’s done, girls he used to know, things I feel like he’s lying about. He’s just so drained now and he can’t handle it anymore. He also doesn’t do the bare minimum which has sucked. It’s my fault that he doesn’t put it any effort anymore though because I hurt him. I guess this is all my fault. For the last few days I’ve been begging him to stop saying mean things to me and to treat me better and to try to fix things. He wants to leave because I can’t trust him. There a certain things I feel like he’s definitely lied about though, idk. I’m so terrified of losing him because we have been together for 2 years and we’ve experienced so much together. We had plans for a future together and he promised he’d move here soon. I’ve spend the last 2 years only thinking of my future with him rather than the possibility of having a future by myself. Today I left my phone at home and went to work. I had training at ulta for 4 hours. I sent my boyfriend 2 paragraphs. One explaining why I’m so insecure and how I just want his love and another telling him how much I love him and miss him. They were a lot deeper than what I’m saying obviously. I truly feel like this is the end though and I’m terrified. I’m terrified of losing him but I’m also terrified of being alone. I feel like no one could ever love me or find me attractive. I feel like I’ll never find a love like him again. I thought a few times in my head while at work of ways I could meet someone else, they were brief thoughts and I think it was just my brains way of coping with the immense pain I was dealing with. There was also a guy I saw walking outside. I moved my eyes very quickly but then looked back. I looked back multiple times. He wasn’t there after the first like 2 times I looked. I guess I kept looking to see if he’d come back. He wasn’t dressed cute maybe, I’m not sure. I couldn’t see his face though, it was cut off. I feel like I kept looking at guys today. In the past I used to always try to not even make eye contact with a guy. There have been times where I have looked at a guy twice but I try very hard not to because I don’t want to be a bad girlfriend. I don’t know why I did this today. I think it’s because I’m so scared of being alone and I know it’s coming. I don’t even know if I found these guys attractive but I kept looking. I wouldn’t stare or play eye tag or anything. I would just look more than once. I’m not sure I realized in the moment but I realized once I got home. I feel very horrible now.