I wanted to pipe in as my H has some similar tendencies around blaming others and lashing out when his (unspoken) desires aren't met. I share in everyone's discomfort with the way he's acting, and absolutely agree that you need to address this NOW with him and his IC before you allow it to continue.
A few things that I have tried with my H that have really helped (with his behavior in these situations, not in the overall "staying married" part so take it all with a grain of salt ) that might be appropriate in your situation:
--I make it a point to ask, ask again, and then get verbal confirmation if we're going to do something that I suspect he isn't 100% into. I saw you did that and then worried that you were acting overbearing and naggy- NO! You weren't. You are trying to communicate with him clearly and get him to communicate with you, which you need to do if he isn't going to take responsibility for his own choices.
--I also try to reinforce him when he does share what he wants to do, particularly if I don't care too much one way or the other-- if he is willing to share what he wants and I'm OK with it, I think it helps him see he can have his own opinion and it is fine. For instance, when your H said he would need some decompression time during the holidays, it might be good for you to make it happen-- find a time where you take the kids and let him know that is what you're doing because he told you it would be helpful for him.
-- I definitely think he needs to work with his IC to figure out why he's doing this mocking thing and how he can stop. This is not something you should accept.
-- Finally, it sounds like you guys need to work out a better way of communication. It isn't OK that you don't feel heard, or that you're worried or scared to bring something up that you feel in order to keep the peace. Then what's the point of being in an R with him? You don't want to go through your life like this and I would imagine you would need to have some level of hope it will change in order to keep him around-- and if he isn't able to take this seriously and work on this now, when will be a better time? I can't remember if you guys are seeing an MC or not, but this could be something to work through with an MC. Or, even both reading Gottman's 7 Principles and trying out some of the exercises with a regularly scheduled time to talk about things? Maybe feels contrived but perhaps if you can set some ground rules that you can both follow and it can be a safe space to share.
Not sure any of this is helpful but wanted to say I can totally empathize with you and am glad you're not going to accept this behavior anymore. It isn't OK and he needs to realize that.
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing