I hope your son is doing much better. I know how kids think they're invincible at that age.
Well I guess you know the answer as to how you've been doing. You seriously need to cut off ties to your W. When I was S from my W, I barely talked to her. Of course, she had an OM to occupy her thoughts.
I can't believe she got you a copy of that self-help stuff that she's been reading. I think she's barking up the wrong tree. You know she could be going through a MLC like my W in terms of her regrets of past decisions, etc.
Just give her space and time to figure that out by herself.
When you go dark, you only talk to her when necessary. If she thinks you're being a jerk about it, let her. She can't TELL you when you can or can't pay attention to her.
JoshuaRoberts has a thread that shows how to detach to the extreme. I have reservations about his sitch because of the immaturity level of his W (literally), but his method could work in your sitch.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.