Your husband is emotionally and verbally abusive, and does not seem to like or respect you much at all.
Your normal meter is broken from years of exposure to him.
You are his wife, the mother of his children. He made vows to love you, to honour you, to protect you, to put you first, to have your back.
Instead, he repeatedly belittles you in public, making contemptuous and derogatory comments that malign you, your character, your contributions etc.
There are any number of reasons why men like him do this:
A. To manipulate others' perceptions of you, either
- to make himself look better in comparison, or
- to undermine your social network and thereby your exposure to outside perspectives and access to potentially supportive outsiders.
B. To assuage his own personal feelings of inadequacy or social anxiety by putting you down
C. To undermine your self-esteem and social confidence, to 'drag you down' and make sure you 'don't get too big for your boots' and 'know your place'.
D. A natural continuation of the casual, everyday contempt he has for you
E. Any delightful combo of the above, plus other things I'm too dosed to think of right now.
...For your purposes, it doesn't really matter why he does it, except in the sense that knowing his agenda can help you protect yourself and your children whilst you take your next steps.
What does matter is that he is a terrible husband and partner.
...That he so resents you laughing and relaxed, enjoying yourself socially, and so hates people to be enjoying your company and thinking well of you, that he just has to say something awful about you, so that you and everyone else stop relating to each other and instead remember just how inferior and flawed and unlikable you 'really' are.
By way of reference:
My partner has never, ever said a negative thing about me in public, much less a seriously insulting, contemptuous thing like you describe. The opposite, in fact - he talks me up, to the point where it can be embarrassing, as I'm fairly modest.
Storytime:
At a party quite a while ago, my partner and I frequently found ourselves in separate little 'gatherings' in different areas of the house. He'd come over occasionally, ask if I was having a good time/tell me I looked gorgeous/offer me a drink etc., but for the most part we were doing separate things. He was playing cards for a couple of hours with five or six others, including my sister. Anyway, the next day, I was chatting with my sister and she said that whilst they were playing and talking, nearly every time he heard me laugh from the other room, he would involuntarily smile and look in my direction. (My sister teased him about it, of course, even though she though it was adorbs).
...The point though, is it made him happy that I was having fun.
There was no desire whatsoever on his part to squash me or smother my socialising by making me look bad or feel bad about myself.
Because he loves me and thinks well of me. He respects me and demands that others do the same. He wants me to be happy.
Your husband does not have your best interests at heart.
You deserve so much better.
I shudder to think what he says to/in front of your children, and what lessons he's teaching them about men, women and marriage.