I know how tough this is for you. You've been at this for about a year longer than I have, and even I already feel I am coming quickly to the same place. My POV has shifted dramatically in the last month, under the constant reminders and unrelenting stress of my own W's dramatic change in character. I don't know how you've held out this long and you are to be commended. No one can say you haven't been giving it your 100 percent.
I cannot say I blame you for now taking an indifferent stance with regards to you M; in fact I'd say it's a healthy response when you find all the tunnels have been cheeseless. Perhaps at this point you really need to not only detach but to withdraw -- not for another 180 or LRT or some other means to hopefully defibrillate the heart of your M, but to allow yourself to let go. Only you can make that decision for yourself. Either way, it's certainly best to focus exclusively on you and your children.