I am just curious why you think OM would give you information about his W and where she works? To me that is very odd and not something that would be shared.
I didn't mention my H's affair for FIVE MONTHS but I knew and my H knew I knew. So, don't be surprised of both OM and your W know you know but have said nothing.
This is simply my opinion but if you strike up a conversation with OM and ask about his W and where she works you are essentially telling OM that you know about the A and he will take measures to make sure his W is kept in the dark or make you look like the crazy person.
