You said it yourself, "Try to set a good example,"
That is the reason we do NOT attend gay wedding or join atheists, Jews, Muslims, Buddhists, Taoists, Hindus in their worship. We are NOT to condone their sins, we are to set a good example.
You are naive on too many things. If you attend a gay marriage, that means you are condoning it. How come you can't understand it. Either you are for God or against, there is no middle ground. If you are attending a gay wedding, that means you are not against it, that means condoning it. You have a lot to learn on way more than just the Bible.