Any advice is very much appreciated

So, I'm going to try and sum this up as much as I can. I've(M23) been in a relationship with my boyfriend(22) for 4.5 years. We've hit a very large rut in our relationship after my depression came back and his anxiety has been horrible the past two years. He wants, at least I think he wants to work on our relationship. The only thing is, I have to lose weight(I'm not obese by any means, just a few extra pounds), and change myself in order for him to have feelings for me again. I miss the way he used to be. He was so caring and loving and the anxiety took that all away from me. We recently had a huge fight where I basically said I need an evening to think about what to do, and on that evening I went on a date with another guy. He was so sweet, something I haven't felt for over 2 years now, and we had a great time. We ended up doing stuff after, only oral, and that night I was honest and mentioned the boyfriend(I told him earlier that I was going through a breakup, because at the time, I thought I was.) and how he wanted to work on things and that I agreed because I didn't want to throw away 4.5 years. I feel like I made the wrong decision and my anxiety has been through the roof. I tried talking to the guy again to try and explain everything in more detail but he basically hates me and has even called the cops because I texted him. I really just want some advice. I want to try and message him again, but I'm worried about what he'll do.