Stuck on my ex in a way but not really.😕

So, I was with my ex for 5 years it was a physical and mentally abusive relationship, but for some reason it was just right? We understood everything about each other. But we never told each other we loved each other. He told me, but I never once told him back. I would just avoid it, but it was there? I found out he cheated on me, but I feel like I ended it in the worse way and I just really think about it every night. I'm happy with my current boyfriend but there are just times I can't help but look at our old pictures  when I'm alone..and it gets me in tearsÂ