You’ve written an articulate and thoughtful letter. Although you don’t want to fight with your wife and acknowledge that you can’t change her, you do spend most of your letter talking about her issues. I think you would get better results if you focused on your own for a time. You don’t need to convince your wife of the wisdom of getting professional help before you get started on it for yourself.
You see, long-term couples (whether married or not) develop a system of communication that becomes cyclical and self-fulfilling. You both know your roles and lines really well. You can’t get out of the recurring drama because you cue each other. If one of you can change your role, the other will have to respond. By going to a therapist yourself, you can learn some new ways to think about the situation and you can learn new skills for getting through the impasse. When you behave diffently, your wife will have to learn a new role as well.
If you decide to go this route, it’s essential that you do it without judgment on your wife. Simply let her know you are starting therapy. Don’t suggest that you are superior for doing so. Don’t pressure her to join you. Just let her know that you want to figure out your part in what goes so wrong between you. Also tell her you’ll be happy to include her when and if she is willing.
Meanwhile, jump into therapy with enthusiasm for the project. At the very least, you may finally get a handle on your pattern of making poor decisions. At best, you may learn how to be more effective in your marriage.
I wish you well.