I agree, you have to stop looking at those sources that feed the images in your head. You are punishing yourself and you have enough to deal with, as it is.
Other than wanting your W to return, have you set any goals for yourself? I don't want to sound as if I am not taking your M problem seriously. I only want to help. The number one successful thing I've seen LBS's recommend is GAL. And, get a life that involves other people, not just a one person activity. Go where the people are, and make new friends. This may be the only chance you have to do whatever you want, without having to consider someone at home who is not interested in the same things.
Be your own best friend. Protect yourself. Don't watch her and the affair partner. You know she's with him, and that's all you need to know. Looking at FB or any other social network, seeing her messages, pictures, etc., only hurt you.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!
