My ex [21 M] is guilt tripping me [24 F] for sleeping with someone else after he broke up with me and I'm really upset

I was dating him for about 8 months. We met on tinder and got along really well. Spent almost all our free time together. We would fight often over stupid things. I was/am depressed about my shitty job and my abusive boss and would take it out on him often. We would break up every month or so for a few hours until we got over it and came back together. I honestly feel like I love him. A week ago he dumped me saying that we weren't right for each other and that he wasn't ready to be in a relationship. He had a bunch of reasons that we weren't going to work out but I don't really agree with any of them because they are so minor and fixable. A few days ago he came over to my house to talk to me about everything because I was completely devastated by the breakup and kept having breakdowns. He told me that he didn't love me anymore and then he told me he wanted to make love with me for the last time and we had sex. Honestly it was nice but I was really upset that he was doing this to me. he told me that we weren't right for each other and I should see other people and be happy. So that's what I did. I stupidly met up with a random guy from tinder and had sex with him last night. He was really nice and I had fun. I honestly enjoyed being distracted by the heartbreak of my ex. Today my ex saw one of my snapchat stories about how I had a good day yesterday and he assumed I had sex with someone else and completely flipped out at me and got told me that he was going to talk to me to try things out again and that he had chances to go on other dates with girls from tinder but couldn't stop thinking about me so he didn't go. He said he wanted to get back together today but I ruined it by having sex with someone else. Yesterday he had messaged me wanting to hook up and said he didn't want to be in a relationship with me and I got really mad at him. I guess today he changed his mind but now he's stuck on how I slept with someone else. He's blaming me now saying that we would be together today if I didn't sleep with the other guy. I feel completely devastated all over again and now deeply regret sleeping with that guy who isn't in contact with me anymore (big surprise /s ). I am not sure what to say to him but I am sure that I do love him and I deeply regret acting out and sleeping with someone else. Should I cut ties with my ex or can I salvage this?