Why do I ruin every relationship I'm in?

I was well kind of still am with an amazing guy. He and I have been together for a month and 2 days now. I’ve never been as happy as I’ve been for the past two months in my life. But we went on spring break and he stopped talking to me…He wouldn’t talk to me until yesterday. We went a week without really talking at all. =/ I left him a voicemail that I basically said if he wanted me I was here if he didn’t I was gone. His friend(D.j) later called me and said why’d you break up with Brendon? I said I didnt but my voicemail kinda sounded like I did I guess. But anyways, at that point I thought Brendon was done with me so I was stupid and didnt feel good so I went and chilled with my ex who was visiting and I madeout with him and stuff. =/ Yesterday I texted Brendon and he and I started talking and he said he was sorry that he just needed a break and said everything was his fault. I told him it wasnt his fault that it was my fault. He said he didn’t know what he wanted anymore. I asked him if he trusted me. Brendon said yes. I asked why he didnt just tell me he wanted to take a break. he said he didnt want me to freak out I said I wouldnt have. I wouldve understood. He and I fixed things yesterday. Aj(my ex) which is Brendons best friend, texted me about 30 mins later and asked if I wanted him back. I told him I was just being stupid and was trying to get over Brendon and that I was sorry. He then said “Wow. I can’t believe you’re going to pick that cheater over me.=/“ I said what do you mean cheater? Brendon hasnt cheated on me…Well…I guess he did two weeks ago. =/ But I also kinda cheated on him as well. =’[

Is it crazy to say that even though Brendon cheated on me before all the fighting started and stuff...that I still want to be with him? He saved my life, no lie. And he means the world to me. I dont know what id do if id ever lost him. We havent told each other ourselves that we cheated on each other. Im confessing tomorrow when I see him at school, hopefully he does the same...

What can I do to save my relationship with him? Everything I do seems to hurt him more and more now. =’[ HELP!!! please..