This sounds awful. I'm so sorry you had to go through this. I think laying out your boundaries as clearly as you did was a good idea, and he simply cannot talk to you like that. I get especially upset with the impressions. I have a few thoughts to share if it is helpful at all:
-- recovery as we all know is not a straight line, and it isn't probably in the big picture surprising that he had this major lapse. The good thing is that you dealt with it well-- even though you are upset with yourself for listening to it, you remained calm and then finally left when he crossed that final line. I wonder if he was pushing and pushing to see where that line would be, even if subconsciously. And then you calmly approached him the next day, shared your thoughts, and he apologized (even if not with a full heart... I'm going to guess that it could have gone worse). So think of how far you've come in all of this.
-- I am thinking back to the "you didn't break him, therefore you can't fix him" mantra. He clearly has issues and is projecting them onto you. He has a lot to work on. I feel sad for him that he is trapped in this awful place inside. But still it is not acceptable for him to take it out on you. I guess the question is how can you give him the space he needs to work on this (assuming he is committed to changing) without it taking such a toll on you?
-- Maybe he is getting better and this was a setback but he'll continue to improve. I know you aren't ready for MC but I'm wondering if a visit to his IC (as I think had been planned but cancelled in the past?) could help, so that you can have a conversation facilitated by a professional where you lay some of this out? or an initial consult with an MC? I mean, he'll never be able to be in a true partnership with you or anyone else for that matter if he can't communicate what he wants in a respectful way, or doesn't really understand what it means to compromise (seems like he feels either he wins or you win, in something like the school choice), plus the issues with perceived criticism and the need for control/feeling disrespected. I just wonder a little if he can even hear you when you articulate some of this to him, or if he needs a professional third party to hear it and help him get there.
-- Your plan about your child's schooling sounds eminently reasonable, if it helps. He is being unreasonable.
As you know I have had issues with my H being disrepectful and mean also, and this is the one area where he's really improved, I think quite a bit from the help of his IC, as we had identified this as a major R issue (I think I was calling it anger management) during MC round #1 and was the primary reason for him starting to see the IC (although I think the A and his ambivalence around ending either it or our M was the bigger, unspoken factor). There are a couple of things I've done that are similar to you and just like anything else of course it all takes time. And if his behaviors are rooted in some deeper insecurities, then he has to deal with those along with the unacceptable behaviors. just a couple of ideas to take or leave:
-- I set hard boundaries around talking to me disrespectfully. I tell him to knock it off. I stopped letting it start a fight. -- While ultimately I wanted him to not be a jerk to anyone, at first I decided to let the small stuff go, like yelling at another driver on the road. if it wasn't towards me or the kids, I ignored it. (And the funny thing here was that it actually really burnt itself out and he stopped this too... I wonder how much of it was really just to get a rise out of me.) -- I really reinforced it when I saw him deal with something well-- not like fake over the top, but I would turn towards him and tell him how much I appreciated X. (And of course as you know H is still disrespecting me in the biggest of ways, so all of this seems kind of mundane in comparison... but for whatever reason this issue, which had been my #1 biggest problem with him (that he acted like an a-hole, was disrespectful and mean) has for the most part gone.
I'm sorry, Alison... I hope this was just a setback and he can take from it that he really needs to work on these issues if he wants a real R with you. I'm sure it is all true that he has mostly been feeling better in the R as he's been expressing to you-- but he maybe just had a down day, like we all do, and drank and then expressed it all in a really dysfunctional way.
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing