I feel like a cheater because I got with someone during our separation

Me and my girlfriend started dating in February. It was good at first, but after a few weeks I realized it wasn’t what I wanted. I broke it off, and she took it terribly. I felt ending it after a month would hurt less than ending it later.

I still wanted to he friends with her, she agreed but was confused why we couldn’t just date. I told her I just was happy being by myself and doing my own thing. But a few weeks later I started getting with another girl who I knew and I stayed over her place 3 times. I also still hung out with her. She still would sleep over some nights, it even seemed like we were dating at times. But there were times when I didn’t want to hang out with her and I’d tell her I’m single and she’s not my responsibility and to stop bothering me. Very manipulative.

So for 3 weeks I pretty much alternated between both girls. After the 3 weeks, I just stopped having interest in hanging with the other girl, I just wanted to hang out with my ex. And for the next few weeks it was just us again, and we eventually started dating again as I realized I was happy being with her.

But now I feel like a cheater, since I was still getting with my ex saying I still love her and have feelings for her, but I was still with another girl too. She didn’t know I was getting with another girl. (She does now obv). It makes me feel we weren’t really broken up, because we still hung out and sometimes it seemed like we were still a thing. I feel it was actually more a break, which is why I feel like a cheater. When we got together, I finally agreed I wanted to date her again, its not like how before, we started in the talking phase which lead to the actual relationship, it was more of me agreeing I was ready to date her again, so I feel we never were broken up, even tho technically we were. Since I kept hanging out with both, I feel I’m a cheater, and it sucks because we both preach loyalty. We both frown on it and both agree it’s the end of a relationship.

I understand all my actions are terrible, but I’m here because I really need advice. We’re actually very happy right now, the relationship is great. I think that this is always gonna affect us, because it happened so early, it kind of defines or is the “first impression” of our relationship. I know some will say it’s in the past so let it go, but there’s things that are in the past that are to bad to forgive and move on.

Am I overreacting about everything ? I feel like Ross from friends. It’s hard giving her all this love now, because I know how much I hurt her before, you don’t do that to someone you love. I wish I never ended it, and I wish I could of just waited to see if I eventually woulda been happy being in the relationship like I did in the first few weeks. She’s been hurt by other guys and I told her before we dated I would never hurt her, and I’m not like them, but thats a lie isn’t it, I broke up with her…. I truly don’t know how/why I wanted to end it months ago, and it has been killing me with guilt all summer….