I often think of contingencies to address things that I don’t think will ever happen. This is one of those things. I have zero information to think my daughter leans this way and plenty of evidence that she doesn’t. But IF she ever confronted me with this circumstance, this would be my response:
No, thank you. You go ahead and have your party with your friends and enjoy yourself. I won’t be paying for it. I won’t be walking you down the isle in a white dress in a church or any of the other customs that we do for a real marriage. What you are doing is a mock marriage. That’s fine. I personally don’t want to mock other people’s deeply held religious beliefs (except Moslems… and Mormons… and Hindus… and Animists… and well, you get the picture), but you go ahead. I won’t be a part of it. What you are doing is having a party to celebrate your mock wedding for your mock marriage. That’s way too much mockery for my tastes. I don’t hate everyone I know that much to poke this stick in their eye and turn it. I expect you will never forgive me for this. But then, a relationship where I am expected to forgive you for your unimaginable rebellion and you can’t forgive me for being utterly consistently myself for your whole life, doesn’t have much room for healthy companionship or even courteous mingling. First you won’t forgive me for holding the line against your stupidity. Then when you realize I was right, you won’t forgive me for that.
It seems like a good speech. It’s a shame to waste it just because I don’t have a lesbian daughter. So, here you go internet. A free speech that maybe one of you can use.