I see no reason for kids to attend a teachers wedding....it's odd gay or straight....We never went to weddings....But as a christian this wedding doesn't align with the Word so I would not want my kid to go even more than if it was a straight wedding.
The story of Job teaches us that the Devil has to be given permission to attack us. So if God is allowing the attack surely He's planning our victory. He would not allow us to be in a battle we could not win.! God looks for hand-picked people He can send into difficult environments, that He might be glorified. He makes all things "work together for good" (Ro 8:28) so don't be intimidated. Just keep your eyes open and see what God is up to!