My interpretation was that he felt she left him because she thought he was weak. I saw the story as a way for him to work through his feelings about loosing her and her daughter because of that. So he writes a story were the character is too "weak" to take revenge on the people who killed his wife and daughter but then in the end he does do it. When he didn't show up at the restaurant I assumed he had stood her up to hurt her. He is no longer as good of a person and has learned how to take revenge, like his novel character.
There is no such thing as too much time
Actually don't think it's that open to interpretation.
maybe edward wasn't really there,
Amy Adams's character in real life never fought to be happy.
She didn't work to save her marriage, she eventually went the easy route by giving in to her mother.