I'm a little puzzled by the tree incident. Who normally handled the yard, yard work and hiring outside contractors. I would have been delighted if mine had gotten off his butt and actually done something.
Maybe I have this wrong, but I think that what bothered you is that you had no control over this situation. That he did it unilaterally without discussion (read your approval).
I think you may still have some serious control issues when it comes to him. That said, I don't believe for a moment that you were a co-pilot in sending the marriage into a ditch. Not unless you mean by your decision to marry him.
I did everything for my H. Everything. I gained weight. He hated it. Said by doing that I forced him to cheat on me and I abandoned him. Do I believe I did things wrong in the marriage? Absolutely. Do I believe I was the co-pilot? Nope. We would have ended up in the same situation regardless of my weight. I have zero doubts on that point. Perhaps it would have happened sooner, perhaps it would have gone down a little nicer, I don't know. But it would have happened.
Keep working on detaching. Own your side of the street but don't take the blame for his.