Where Were We 2008

In a book that I once read, a young woman asks her lover to never forget the special day that they spent together and the place that they were together in. She asks him to promise that he will never forget this day and place. He promises that he will always remember and that no, he will not forget. But he forgets. He can remember the place quite clearly, down to the last detail but he can't seem to really remember her on this day. And he can't remember the important thing about that day, the thing that he promised never to forget. He can't remember what they did. He always thought this distance or lack of clarity might help him to really understand what happened to them, but he can't remember the main thing, the important thing...