H...it is never too late to change your behavior with your kids. I read over your text exchange with your W. It didn't seem to be very productive and there also seems to be a lot of hurt, anger and resentment between you both. Your MR may not be able to be saved but how could you move past your own issues and maybe be the voice of reason moving forward with your W?
Could you do this for the sake of your children? I just get the sense that someone has to step up.