Amy: So are you feeling okay? No wedding jitters?
Sheldon: No. There is nothing in the world that would stop me from marrying you tomorrow, even me from the future coming back to prevent the wedding and the subsequent birth of a child who will destroy humanity.
Amy: Because if you came from the future, that would mean you already went through with the wedding because you believe that time travel is on a closed loop.
Sheldon: I love you so damn much.