Personally I would just show up with your husband anyway. RSVP with both names, and make it clear you will be brining him. Hopefully they are polite enough not to start shit at the wedding, but of course their your family and only you know what they're capable of. I'm not a very classy person, and this would be quite the act of passive aggression. My partner is trans too, and I'm at the place where I'm thinking of introducing them and bringing them to Christmas . If my family has a problem with it, they better keep their mouths shut because I am a part of my family and I will bring my partner with me. If they have a problem with it, they can stew in their own illogical self-imposed transphobic box.

I especially hate the term "inappropriate." I've heard that too. WTF, why is a person who is trans "inappropriate"? As if a trans person just existing is inappropriate. People have behaviors that are inappropriate, not people themselves. People act inappropriate they do innaporpriate things, they themselves aren't innappropriate. Me wearing a bathing suit to funeral is inappropriate, having naturally red hair and myopia isn't inappropriate. Being trans in attribute of person, not a behavior.