u/69_420___

I’m fascinated by the nuance of human fallibility. I’m looking for book suggestions where a main character is unfaithful, but the writing is focused on the internal drive and the "rationalization" of the urge.
I’m specifically looking for books that are not moralizing. I don't want a story that ends with a clear "this was a mistake and here is the punishment." I want something that treats the protagonist as a whole person—someone whose choices are explained by their history, their environment, or their own internal logic, however flawed.
Essentially: Infidelity as a window into the human condition, not a plot device for a lecture. Any suggestions?