(((safe hugs)))) Of course your feelings are valid! I wouldn't go. Sorry, I would ask that they plan another dinner or time or event where you can get together with them "alone." You have every right to be upset. It's their problem that they don't see a problem with this..and IMO that totally discounts what he put you through! (not in my eyes, but in theirs) If they don't understand, they never will, and you will be resigned to putting up with it the rest of your life.

Just say, "No. Thank you."