I am now going dark. What is everyone's thoughts on telling her that I am going to start dating someone else?
I think you're insane. The very next thing you say is "we're going to have time, which is what we need" and the above is your plan? You actually WANT to fix your M right now. At least it sounds that way. Why the heck would you intentionally make things WORSE?
Lying about dating is being cruel for the sake of being cruel. I promise you that will not make you feel better. I promise that will make you feel worse.
ACTUALLY dating will do nothing but complicate your life right now. It will not resolve your feelings about your W. It may actually make them more ambiguous. You WILL drive an even bigger wall between you and your W (I promise, no matter how high and thick the wall is, it will get higher and thicker, no matter how impossible that seems).
I remember your first thread. I remember thinking that you were a lot like me in temperament and personality. So here's what else you'll get: you get the joy of questioning if you're doing the right thing. Doing things for the right reasons. Involving yourself in someone else's life for the right reasons. No matter how many times you answer those questions affirmatively, you will ask them again, because you know your perceptions are untrustworthy and you're not sure if you're working with good data.
I also think you're enough like me to ignore this advice. But assuming you're smarter than I am, your plan to go dark sounds like a good one. Detach. GAL. Don't worry about what she's doing or who she's doing it with. IF you want your M back, that's the ONLY way it's going to happen.