Realising you fucked it up

Does anyone else realise more and more of the mistakes they made during the grieving process. As I'm processing things, I'm realising more and more ways in which I messed up or made him feel misunderstood and it's making me feel worse. That at the time I never realised how much I was hurting him with my actions.

I know I should be able to look back and say ok I made a mistake and move forward knowing I won't do that again. But instead I just feel so devastated and like I failed him. It leads to this awful cycle of self blame and hatred and I wish I could just tell him I'm sorry. I know it's too late and won't change anything now.

A breakup is one of the biggest life lessons there is and I'm learning that even though I was trying really hard I still managed to screw up something that was so important to me.