Quote: This would be far easier if he would come to me...
I would be, but what's the chance of that? He brought it up once and I would say is not likely to do it again.
Can you simply tell him that you want to come up with some solutions to what is obviously going to be a difficult/awkward situation for you both! Think about what types of things that he can do to make you feel ok about working with her for a week. On his side, maybe you can help him brainstorm some responses for possible situations that may come up between him and OW. He may be feeling just as insecure about this as you are.
Or, he may truly feel that the A is totally over so it isn't a big deal because there is no feeling left. I know people want to know how my H can invite FF over, knowing how much I dislike her and I know he feels that there is nothing going on, she's just a friend so what's the big deal? In that case, I still say talk to him about some things he can do to ease your discomfort. If you don't, will you just spend the entire week making up horrible scenarios about them getting back together?
Just some thoughts. Hope it made sense.
Erin
"A life spent making mistakes is not only more honorable, but more useful than a life spent doing nothing."
-George Bernard Shaw