Terp,
I understand the difficult dilemma you're in. I'm sorry for the hurt you're feeling.
One simple day at a time, by working a 12 step program, my life is changing in amazing ways. I debated for a very long time whether Alanon was what I wanted or was willing to do, what it's merits where, etc. I found every excuse possible to not walk through the door, and then to not go back again. Now I have found time and again that it doesn't matter why it works, just that it does if I am willing to do the work. It took me a long time to be willing, and that's okay. I'm getting to a very good place in my life in my own time.
I have several Alanon friends who swear the program saved their lives, but the only reason they did the work was because they were determined to prove the program doesn't work. And then they found it did.
It's not the only way to heal, it's just one way that's helped many. There are other ways to heal also. Awareness of how you're feeling and wanting some kind of change sounds like good places to be, even though they can be very difficult places to sit in.
I found time away from my husband critical to my recovery, so I would have time away from my subconscious responses to him.
Do you have work you enjoy or find rewarding? Hobbies? Physical activity to let out some of the frustration?
You are important. It's okay to hold onto any sadness, anger and resentments until you're ready to let them go, in whatever way you find. That isn't for him, it's for you. So you can be at peace. When you do let go of them, it still doesn't mean you need to stay in your marriage. He left it first, a long time ago. There is no need for you to feel any shame or guilt in either staying or leaving.