not a peep

[Dom R]

judging by past events.. i'm guessing the only effective way to de-escalate, is just to not talk to him for a few days.

let him cool off, see if it helps.

PS:

I guess I need to come to terms with the idea that he is done. That the marriage is too broken to fix and that there really IS too much history

you may come to terms with the idea that he is done trying right now..
but in no way is there "too much history".
That is just sad.

There are some marriages out there which really DO have "too much history" to deal with easily.
10 years of adultery. Years of physical abuse.

Your marriage has none of that. All it has, is a selfish, ungrateful prick