Have been away from HS for a long while, returned and stumbled immediately into this thread. It's long, it's fractious, it's illuminating and thought provoking.
I agree with the poster (sorry can't remember whom!) who wrote that our responses to MLC likely reflect our own stages, more than those of our MLCer. I think we all go through denial, anger, bargaining, depression and acceptance, not necessarily in that order, and sometimes circling back to some stages but not others. And while I was in denial, it wasn't my MLCer's fault; while I was angry I truly wanted to set my MLCer on fire (I hated that, so I mostly skipped anger); some of my worst decisions were because I was bargaining with the straw man MLCer in my head; etc etc. I think my MLCer was oblivious to my stages, as he was densely oblivious to me, during that period.
In the end MLC behaviour seems part volitional, and part not. Like an alcoholic transfixed by the bottle on the shelf; like the OCD patient who knows washing his hands one more time will cause them to bleed but he just can't stop himself; like the person who punches through a glass door in a rage, knowing he will shred himself but not caring. My H remembers most of what he did (though very little of what he said... I think he blocks those memories), and knows he chose the actions; he refuses to cop to mental illness. But as another poster said about his own spouse, my H chose the action, without choosing the outcome. A lot of mindless thrashing, followed by shock/despair/reactive anger, followed by more mindless thrashing. I don't acquit my H of causing me pain; I think he caused himself a nearly equal amount of pain; and it was no more reasoned through than a rabbit caught in a trap. But of course he's not a rabbit; and whether he chose it or not, he owns all of it, volitional or reflexive.
That is precisely why, when my H returned, Sorry was the most difficult thing for him to articulate. Still hasn't, really, though he acts it out in every way. In his (idiosyncratic!) view, he's not allowed to apologize for something he voluntarily did, that's facile. He feels he can only try to make it good somehow (...okay, that'll take you years, buddy...).
But that's his problem. My problem? To detach. Guess you can only become compassionate after becoming dispassionate. And once I was at a safe enough distance, I couldn't actually be hurt anymore. It's only at that safe distance that I could begin to decide whether to forgive. And to trust my own judgement enough to let myself do it.
I think there's space for all of these endpoints on HS. Not all of us run through the same stages. Not all of us wish a return. Not all of us permit a return. Not all of us forgive, in the end. Not all of us have to. All of us do grow, though. That's the only gift of time OP refers to, I think.
"You have a right to action, not to the fruit thereof; shoot your arrow, but do not look to see where it lands." -Bhagavad Gita