Tl2, I am sorry to hear how things are going. I just want to say that I really really appreciate you sharing your story. I have taken notes! And I plan on implementing some of the things you have put in place to help you get through this difficult time. It is inspirational.
Your compassion for your wife is amazing. I too have been married 20yrs + so I understand the history. That's the mother of your children and it sounds like you have given this everything you've got. From an outsiders viewpoint, you can see the poor choices she is making and it's sad, but I can see the reason for detaching and letting her make her own choices, as poor as they may be. When you are long gone and she is still unhappy, who will she blame then?
I know the loneliness is hard, but it sounds like you are making wonderful improvements in yourself. From reading this, I see that you are hardworking, faithful, loyal, a great dad, you are working out, you love nature, you have a good sense of humor and can hold a good conversation, and you have a strong faith in God. I don't know what will happen with your wife, but if things don't work out, I imagine you won't be single for very long...