L,

I know and feel your pain. I am getting divorced after my husband of 18 years moved out and left me and my three children. Same story-unhappy,resentment towards me over his unhappiness, nothing I could do would make him happy.
You have the inner strength to get through this. You need time away from him to build that strength. He is in a bad place that you can not change or control. You can only control yourself and right now that means protecting your strength that you need.
It would be helpful to find someone that is a friend that can be a supportive listener. Maybe even find a support group for separated woman, even though you aren’t they will understand your feelings.
Trust in your own strength and you will get through this.