She notes that Mark was always cold towards her, and that being as he's such a good friend to Peter, they could become friends as well. Mark uncomfortably tries to keep her from seeing the wedding video he shot, but she finds it, and quickly realizes that, while it turned out beautifully, the entire thing focuses solely on her. Mark was smitten with her, but never said a word in deference to his best friend, calling it "self-preservation."
He later comes by their house, and Juliet answers. Mark uses a series of posterboards to confess ("without hope or agenda") his love for her before leaving, knowing it's time to move on with his life.