Thanks everyone, for the replies.
I'm going to "suck it up and go" but I did tell DH that if the owner makes a nasty comment to me I'm getting up at that point and leaving. He can either come home with me, or he's welcome to stay with his family and get a ride home with someone. But I refuse to sit there if the manager says something nasty to me like the last time I saw him. And he agrees with that. DH used to work for the owner, so I'm sure he will say something to DH (he adores DH) but he just better ignore me like I'm going to ignore him!
Yes, I will probably just order a salad. I know they don't have gluten-free pasta or anything like that, that I could eat, but they have a chef salad so I'll just go that route.
And we're not paying, DH's Dad is paying for everyone so it's not MY money that's going to the owner so that's a good thing.
I used to get out of these family gatherings because they always do them on a Saturday night and oh gosh darn it, sorry but I have to work. So sad. NOT!

So DH did go to most of these gatherings over the past 8 years without me. So now that I'm not working he feels I should suck it up and go with him, so I will, for HIM.
I'll make him rub my feet for an hour after we get home, then we'll be "even".
Thanks again, everyone!