I walked away from my actual family 25 years ago after spending a lifetime trying to fit in.I kept in contact with my eldest sister and youngest brother and maintained a distant relationship with the rest, (3 sisters, 3 brothers).
My youngest sister is the main problem and is very controlling and manipulative. I refused to be controlled or manipulated and was ostracised, and rarely go to family events, which to be honest, I don't miss.
I decided 25 years ago that I wouldn't pit myself or my daughter through the dramas my sister kept creating. I now have a far smaller, happier, peaceful family life consisting of my daughter, her husband, 4 lovely GC, 2 sisters and 1 brother.
It is hard to walk away from family but sometimes the peace of mind and lack of stress is more than worth it.
To the OP, be civil in their company, your normal cheerful self, (or slightly over the top), and avoid shared holidays or stay-overs. Make plans to be elsewhere and let your husband visit/holiday with them. (But not in your shared home!)
If he can't or won't stand up for you or see how they treat you, let him visit on his own. You've tried your best, and it's not your fault it failed. Any problem they have with you is just that, Their Problem.
Let them go and enjoy your life without them.