I'm sorry your hurting

Closure? Well It's pretty rare to really ever get it. Life just doesn't give anyone a nice neat closure with a pretty red bow on top .

What I will say is .... Regardless of the reasons the relationship failed .. You will learn something. Good and Bad. I feel based on your post that it just wasn't healthy at all. Learn from this and next go around with someone new you will have a better idea of what you are willing to accept and allow in your life and what you will not.

Grieve the lose of the relationship , it was long term so there lots of baggage to work through , process and put it to rest.. If your not sure where to even start you might want to see a Therapist to help you figure out where to begin.

I hope your feeling better soon