Pam, you sound like you are in a good place, uncomfortable, yes, but a place where you know what you know and you know what you can and cannot do.
You know that he is not as into the OW as he used to be, and gaining momentum out of the R with her. You know that she can't hold a candle to you in terms of stability and maturity and 99 other things. You know he is down there, but you don't know if he is getting closure or not. That is OK, bc if he isn't, this is nothing you can close yourself.
You know that your conduct and attitude helps out your sitch. He has to do the work of getting his brain back and getting his stuff together without you, because you want to be legitimately in his heart, not wrangling in there. Sometimes I want to know all the grossness of my H's actions- is he sleeping wtih someone, flirting with someone, or contemplating it all? I am tempted to snoop, but what would it get me? bitter, angry, mean, jealous, crazy insanity. I think I will just take today, and what I know today, as that is about all I can handle. I will hang in and believe that G has a spectaclar plan for me, much better than I could have made for myself. Is that too hokey?
Take care and treat yourself nicely while he is gone! Anne