If only my WA SO would also end the affair, I think we would have a chance. But you and I know that these affairs usually end at some point. However, the bad thing about this is, we don't know how long this will continue. It could be weeks, months, years down the road. That's so very hard for us.
I do think your DB action is what you have stated, however, I don't think you need to confront your WAW just yet. In my sitch, my SO knows that I know what's going on. We never talk about the OP or R. I just try to keep our conversations on a friendly level. By being her friend, it's the only way she may come back to me.