BG, I was actually expecting you to be the one to BD after all that! Was really surprised that he did. What are your feelings on all this, it sounds like you haven't been happy in the R for quite some time, is that the case?
Are you hoping to save the M? If so then you probably already know what to do since you were here before- detach, leave him be, drop all pressure, continue to get out and GAL. It sounds to me like he is going through something heavy, maybe MLC. If you're able to give him a lot of time and space then he will start to realize that YOU are not the problem, HE is.