In the first incarnation of my novel (now happily binned), my main character was a Canadian art history student. Unfortunately, no matter what I did to make her more interesting (including more of her back story, giving her more interests, etc.), she just wasn’t compelling enough to carry the narrative. My writing was struggling as a result, and I could not make it believable that a cosmopolitan Parisian would be intrigued enough to pursue a relationship.
So, Sophie lost her main protagonist status, and has been relegated to a secondary spot. The novel has done well since then and I don’t even mind having to start over. She still has a role to play in the new draft, but she is not required to provide her point of view. I’ve left that up to two other more compelling characters.