I also feel awkward when W is around and I know that as we were friends in the past, light convo is important. Just so W has a good time while we're together. If it's always too serious and about logistics, the only time she'll be having fun convos will be with the OM and that's no good. I'll look into the conversation starters.
As you see the interaction, the thought of her will strip your esteem down. It will keep going down, down, down, down till you feel like you can't do anything right around her and even physically more clumsy. It's because a significant "mirror" in your life a "former supporter" is not turned on you.
you need to get support from elsewhere. I went down into a deep dark pit behind what brought me to db-land and let me tell you. People get into a lot of trouble getting taken that low and can even hurt others or themself in the process.
Just be mindful of it. Don't bother to talk about it to her. I take it, we have to accept someone is "gone" when they have decided to be gone and move on. We all got on here in hopes of restoring our relationship, but in order to do a proper 180 and GAL is you have to accept for now and the forseeable future, they are gone.
Her mind and thought process is currently focused on the OM, on how much she loves him, on falling for him romantically and sexually, and it will grow stronger over time. The more of him in there, the less of you are in there. I'm getting you to understand that if you can get it back, it won't be a slow or easy process.
A couple of people on this board have gotten lucky when the OM or OW in itiated violence or put their spouse in harms way, and that woke the spoouse up quickly and they want to come home...
