Not sure if this is relevant or not, but as I read the OP, this event came into my head:
My ex would sit brooding/sulking in the kitchen,refusing to engage or participate in his son's 2nd birthday. Or his 3rd for that matter.
I was annoyed, but carried on making my little ds's birthday as good as I could in the circumstances. He was happy and that was all that mattered.
I bollocked him took him to task over it, and it cane out that his mother would just open the door to the hallway where he was playing and say 'by the way, it's your birthday today'
She was a 'rich' woman, pillar of her community etc, well respected, savvy. She'd longed for a child, and was told by a gazillion doctors that she'd never have kids. So it was assumed that she adored her ds. (my ex)
Turns out that this probably wasn't how he felt about it all, and that evidence points to the fact that actually their relationship was 'difficult' (she never hugged him for example)
I wonder if your H sees how 'normal' your family is and somehow on a subconscious level it reminds him that he didn't have this.
Maybe the rudeness is resentment?
Will prize my behind out of the shrink's armchair now, but if this rings true, you may have a way for him to feel differently.
Talk to him - calmly - and see if you can find out what's at the root core.
Ultimately though, he has to understand that his behaviour is unacceptable and he will have to stop it, or he'll kill your relationship with him.