In all honesty OP, I'd continue to refuse to have sex with him regardless of whatever shit he pulls trying to ruin the holiday.
It'll actually work in your favour to have his vitriol and moodiness witnessed by your DC and their partners.
It will simply show them exactly how horrible, selfish and coercive he is to you and them when he doesn't get everything his own way.
If you have any money in joint accounts, move your half immediately with internet banking.
When your DC ask 'What's wrong with Dad', tell them the TRUTH.
No sugar coating, no minimizing, just the facts. He's having a tantrum because he's not getting sex as and when he demands it !
Make plans with your DC's and their partners, doing the stuff you all enjoy.
HE can either join your 'group' or fuck off on his own.
Don't let his sour puss and stupid comments bother you, just either laugh and say 'I'm not interested in whether you're going to the supermarket or not. If the kids or I need anything, we'll go ourselves' or completely ignore him if he's spitting out passive aggressive 'comments'. Just totally blank the fact that he said anything at all !
Mark this holiday as the time you stopped dancing to HIS tune, and began your plans to leave him.