I'm glad to be reading this thread today, when my STBX is coming by to get what's left of her things-- and I hope ALL of what's left, so that we will be done with it. I kept thinking about everything I could say to her, but reading this thread and seeing how that long, long "you" letter got cut down to just a brief "I" statment was inspiring.
I don't expect that she will want to talk about anything at all. That's never been her style. But if she does press the matter, then I don't have to say anything more than "I didn't want to get divorced, and I still don't. But I will not stand in your way. And as long as you continue with OM, I will not be your friend." That's it. No blaming, no remonstration, no shaming, no nothing. Just this. But we probably won't talk about anything anyway-- she'll just silently (and quickly) gather her things and go.
My only concern had been that she might bring OM with her to "help move things" (totally unnecessary, as everything is in easy-to-carry boxes). I had, here, too, imagined all the awful names I wanted to call him and bile I wanted to spit at him... but no. None of that. If he shows up with her, then I will just firmly assert "you are not welcome here" and go inside-- refusing to give over the key to move her things from the storage area-- until he is gone. At this point I doubt he would be there, but that's the only thing that I worried about, and this thread has helped me see the simplicity of my response.