I don't know if the others agree or not, but I see no problem if you want to leave her standing there and say you are going out. Then turn off your phone and go get a room for the night. Either that, or tell her to get out. (Don't worry, I don't mean permanently, but she doesn't have to know it.)
She needs the mess shocked out of her. I'm serious. The fastest turn-arounds I have seen has been when the H would not even try to discuss anything with her and got the heck out of Dodge. It would cause the WW to forget about OM and all that was on her mind was getting her H back at any cost. She suddenly finds herself as the WAS. I really believe men lose a precious window of time by "talking". She is not prepared, yet, to hear any of it.
This is not the usual advice given by DBers, it's just my own. I guarantee you it would have yanked my tail around fast if my LBH had done that very thing.
I for one, could not agree more.
Everybody hurts. It's part of life. Don't miss the good stuff.