Who is Marie from How to Live Safely in a Science Fictional Universe: A Novel and what is their importance?

Marie is a girl who does not exist. The narrator has never met her, but he should have met and married her. Charles also refers to her as The Woman I Never Married. Marie serves as a symbol of everything Charles has done wrong in his romantic relationships, as well as the things that he should do right. In a funny way, she is yet another person with whom Charles has no relationship.