After years of living separate lives, in this moment, Dexter and Emma at last start to become more honest with each other about how important they are to each other. When Emma admits that she thinks of Dexter and is afraid of losing him, it is one of the first times that she communicates her feelings to him directly rather than from a sarcastic distance. And so, Tilly’s wedding ends up also being a milestone in the relationship of Dexter and Emma, even if at this point, all they agree to be is friends.