Texting an ex

Ni

I have an ex that I was with from 18-22 (im 26 now) we lived together and were very serious. Everyone was sure we would get married one day including myself. The relationship was secretly extremely toxic on both ends and we were so young. It really haunts me tho how toxic and horrible I acted. We’re both genuinely good people outside the relationship but together, we were horrible to each other. I want to reach out to him and tell him I’m very sorry if I caused any trauma to him and just hope he is doing well. I don’t want anything romantic with him I just feel so horrible sometimes about this. I want him to know he wasn’t as horrible as I made him seem. I made him sad sometimes. We had pets together and I still have those pets. I had a lot of trauma and PTSD from my childhood that was untreated and it made me act in a way I never would now. (That’s not an excuse at all and I don’t plan to say that part). Is it better to just not reach out? Or is it okay?