When Elected, Trump was supportive of Gay Marriage, Obama and Biden were not. Hillary was against it until she was for it.
The only caveat Trump mentioned was that Gay Marriage should be decided by the States, not Justice Kennedy.
I’ve always felt that had the Supreme Court not passed gay marriage, Trump would have never gotten the nomination because, he would have been forced to admit he was for gay marriage, which would have made him lose a lot of support from Social Conservatives. Once the issue became a moot point, Trump never had to even address it.
Show me where Trump specifically said he supported homo marriage. Yes he did say marriage should be left to the states. He also said once the Supreme Court had ruled on it, but he also said his personal definition was what it always was,