nope...never had an affair. Detached means moving on and your need to know means you haven't moved on...you haven't detached.
Let it go. Assume you will never know. Detach...Detach...Detach. You are hurting both of you with the obsessive need to know. Accept that somethings you may never know.
Displacing your anger and betrayal onto the other man doesn't mean you have forgiven your wife. Neing angry at his behavior doesn't help anything. He didn't betray you and your marriage. SO if he were truthful with your wife and they really loved each other...you would be OK with them being together because you have truly forgiven your wife and detached?