Sooo, I didn't take anyone's advice including my own. Couldn't just stfu. Sent an email, in response to confirming parenting-and car-sharing plan for our upcoming holiday weekend...
"Sure. That plan sounds fine.
"H, I'm so sorry for my role in bringing us to this place-- where you've lost hope for our marriage and feel like this is how our lives have to be. And I do wish you peace and happiness in this new year."
Already knocked myself in the head with a 2x4. So be gentle on my bruised noggin.