Thanks friends for your input, I agree that he has been trying to manipulate me to get to do what he wants to do. So far it has been not so hard to stick to this boundary. I won't say I never second guessed myself, but fortunately I have seen the "catch" behind my thinking. For example, it was fine for the past year or so for me to be unhappy every time he went out to bars drinking with my car. But now suddenly it's not acceptable that he is unhappy because he can't do what he wants.
I think it is becoming easier to enforce boundaries because I am less connected to this relationship at all. I am less fearful if the relationship ends. This has been such a long time coming, but I am not going to beat myself up about that.
I have come to understand that I was codependent long before my AH came along. I see examples of codependency all over my life. A recent example: a church friend has invited me to go to the ballet with her on Sunday. I have done this several times in the past, and the last time I told myself I would not do it again. She always asks me at the last minute, she really wants someone to drive her there, and she always wants to go for an appetizer an a drink after. I like the ballet ok, but this takes up my entire Sunday and I don't like it that much. The point is that I don't want to go. She called me again this week, and I actually considered going. This is the people pleaser in me. She left me a message, and I was tempted not to call her back until today, but I made myself call her and decline, so that there was no chance to give in. So you see? This woman and I are not even really good friends and I feel obligated to do what she wants. I understand now this is not about AH, it is about me. Finding what I want and having my own life.
So whether I am with AH or not, I need to work on me, being more free to be who I am. Finally at 50 I am getting this. I guess better late than never.