I'd like to add to your statement about the MLCer being stuck at the point where the damage occurred. HB indicated that the LBS might see several "children" emerging, and I certainly found that to be true.
In my H's case, his mother (who everyone talked about as though she were Mother Theresa) also had a very angry side. When he was young she'd lash out only at him, so he'd take refuge in his (not-so-secret) hiding place, seething with fear and guilt. Once he reached Depression and Withdrawal, some nights my H would lie on the bed looking scared, and sucking his thumb with desperation, looking as though he didn't think anyone could see him. It was unnerving. I strongly believe that was the issue (and age) he needed to revisit and resolve.
At the same time, however, his C identified him as thinking like a 14-year old, and I believe it's quite common for MLCers to be stuck in "teenaged thinking." I don't think this necessarily means that a second sort of trauma happened at that age. Rather, during puberty the brain is completely rewired--but because the MLCer was stuck during an earlier stage of development, the rewiring isn't properly done. And, sooner or later, any faulty wiring is going to cause a huge conflagration!
To get beyond the teenaged thinking, the C worked with my H to recognize the difference between what his teenaged brain was telling him ("Why shouldn't I have an OW if I want one?") and what his mature brain thought, and how to keep switching back to the second one. It was a HUGE battle for H to get to the point where his mature brain was fully in charge, and he felt so proud of himself for fighting the addiction of listening to the teenaged brain.
It must have been 6 months after beginning Acceptance (if that started with him saying he wanted to work on our marriage) that H shook off most of his teenaged thinking, and became happier and more affectionate. Several months after that he began talking about some aspects of what he'd done, and recognizing how and why they were wrong. Perhaps a year and a half after that he said he needed to fully forgive himself for all the hurts he'd caused me, and then stop carrying the issue around with him.
