Maybe your focusing to much on the OM when you should be focusing on YOUR relationship with your W. What does it matter if he wants or doesn't want a relationship with your W when your W isn't treating you as a H?
Your relationship is dysfunctional regardless of if OM is involved or not. If this guy decides he doesn't want her, it doesn't mean she's necessarily going to come running back to you.
First, you need to identify your part in your W's behavior. If you identify it and realize it's something you can remedy or improve in yourself, then that's the only control over the situation you will have.
I understand the anxiety, fear of loss, and your need to fix it quickly, but it doesn't work that way. You only have control over your own actions/emotions so that's where your focus should be.
Forget about the OM or your W's behavior or whereabouts,it will only drive you crazy.
"It is curious that physical courage should be so common in the world and moral courage so rare." -Mark Twain