I will post to you tomorrow on this thread what I am going to do or not do.
I would not go. If you are as close as you say, tell him. He will understand. His funny friend may not.
I would not attend. Family is very important but if you don't adhere to your principles, nothing else matters much. I would tell my cousin that I love him very much and wish him the very best in life, but I could not attend.
Interesting posts to be sure. I say since your cousin and his 'other' were good enough to come to your wedding ( as you requested) then you now should return the favor.
If you wanted to make a stand against his 'beliefs' you should've started by inviting him to your wedding WITHOUT his 'other'. So I can't see how you can now say they're not good enough to 'accept'.
OTOH the chances of this marriage lasting too long are practically nil, but your cousin will always be your cousin and could probably benefit from your future counsel when his 'failed' marriage occurs.
I have learned a lot of positive things from these responses. After reading them, I would say if it is a civil ceremony I would go, but if it is going to be a "religious" ceremony, I honestly don't know. That would be hard. Maybe I still would. But a civil ceremony would be far less of a problem for me. He did come to yours.