Broke up with my soulmate

I am heartbroken. It feels like my world is completely falling apart. I love him so much this hurts so much but I had to do it! I spent 3 years with him...I found out that a year ago he had a dating app and who knows if he’s been on it from then and now. I told him to delete old contacts and he downloaded an app to store them all in. I thought he changed but I guess it’s true they never change. I thought things were different, he seemed to have changed. I told myself he wouldn’t hurt me ever again, and now I left. I don’t know how to do this, he’s always been the one to leave me, and now I left and he’s begging me to stay, he tells me he’s going to fight for me. Why am I so stupid? Why do I want to be with him? I know I deserve better, I cried for hours last night. I know I don’t deserve this. I was a great girlfriend, he always took advantage. The first year of our relationship he did a lot of stuff to me, and I took him back and we’ve been together ever since, and I thought things had really changed. Why can’t I ever be enough for him... why am I never enough for him? I was a good girlfriend, I had trust issues but because of HIM and I was working on it... but I was a great girlfriend I really was I never did anything wrong... why was I not enough? Why couldn’t that be enough? Why did he always show me that other people were better than me? I am so heart broken, I wish I could be with him but I know I just can’t anymore...