How could she feel nostalgia when he was right in front of her? How can you suffer from the absence of a person who is present? You can suffer nostalgia in the presence of the beloved if you glimpse a future where the beloved is no more.
Milan KunderaThe psychological and physiological mechanism of love is so complex that at a certain period in his life a young man must concentrate all his energy on coming to grips with it, and in this way he misses the actual content of the love: the woman he loves. (In this he is much like a young violinist who cannot concentrate on the emotional content of a piece until the technique required to play it comes automatically.)
Milan Kundera