Supporting your children's successes is not admission of agreeing to the decisions they had to make to attain their success, but Mr Pat Robertson disagrees.
He continues to draw unfounded logic, stating "What if somebody wanted to marry his dog?" Legalizing gay marriage is not a "gateway" law (like a gateway drug) to bestiality or pedophilia, but why would you follow a religious leader who wants you believe that it is?
Support your children in finding love, and if you disagree with where they found it, keep it to yourselves. The wedding ceremony is a celebration for them, not for you or any of the other attendees, and if you allow your "family values" to interfere with your appreciation of your family, we can only hope that you soon find yourself without one.