By the grace of God

[HaWho]

Definitely he is stuck on past hurts. And it sounds like you are tired of trying/feeling your own hurts.

If you want to try last ditch efforts, when next you talk, I might say to him: "h, from our last conversation, I hear you are very hurt by things from our past. How can I help you heal from these things?"

My suspicion is he won't have a "solution." I suspect he'll continue to vent about things that can't be undone.

If he starts to complain again about things that happened years ago (that you have already explained/already apologized for/can't be undone), I would validate and again say: "I hear you are hurt, what exactly can I do to help you heal?"

Like most people stuck in a loop, he doesn't realize he's stuck. It happened. It can't be changed. It's only insurmountable if he makes it insurmountable. Of course he can't see this.

Pulling away from him only gives him more to complain about and reinforces to him that you aren't "there for him" and "here you go again pulling away." I know it stinks but that "doesn't work," so I'd stop doing that. Try the opposite: asking him for the solution.

Perhaps asking for solutions might nudge him to realize that yes, that all happened. Yes, that was then. What now?

And then, again, only if you want to try as a last ditch effort end with: "well, I am here to help you move forward if you have concrete ways I can help." But unfortunately, he needs to understand that "now is the time to try to heal these rifts as we can't go on like this forever. This is not an ultimatum, more just that it's time to fix this or move on as as we've been stuck here for years. Both routes will take tremendous work in different ways."

At some point we all have have to cook or get out of the kitchen. But maybe you've already thrown down your apron and walked out of the kitchen yourself?