His nightmare are a result of your actions. I am three years out and just last night i was woken at 3:36 AM from a Dream of my wife's betrayal. I have had EMDR, HH 2 times been in IC and CC for Three years. Last year at this time coming back home from a Labor day weekend I had a panic attack while driving. Realization we had to go back to home where the betrayal occurred. You cannot forget the effect this has on a person, imagine if you were beaten and raped. How long would the dreams come to disturb? It will lessen for him in time with the intensity to be a nightmare. It will just be a disturbing dream but no you don't forget. That the person you thought would protect you and your family, was thoughtless and betrayed everything you held sacred. Like Christ, our walk of betrayal we pay for it alone. Don't make him walk it alone.