It's kind of nice to know I'm not alone in my frustration and "obsession" to know the details. I would really like to have the situaiton as described in "Not 'Just Friends.'" The book uses the analogy of a house with windows and walls. The spouses have open windows between themselves (open communication and no secrets) and walls between people outside the marriage. That way the openness and intimacy is within the marriage. In an affair the windows are open to the OP while the walls are set up between the spouse.
I worry that he's always built walls up to me (he's never been the most open communicator), but was able to share his most intimate thoughts and secrets with OW.
There is no arriving, ever. It is all a continual becoming.