Perhaps he feels guilty and thinks coming clean is the only way he can get it off his mind. I would not look at it like he is trying to hurt you unless of course his tone and body language showed it was to hurt you.
The more important question would be why he wanted to run off into tbe sunset. What was he looking to find? It was a fantasy for him. Even if he did go off chances are it would have never competed with the fanfasy in his head.
Me: 30's W: 30's M: 12yrs EA: Started 3/2015 MC Started: 4/2015 She moved out and served 6/2015 PA: Confirmed 10/5/2015 2 young kids
"If you do not stand for something you will fall for anything."