Nick is the son of a single mother.
His mother didn’t start out single. She gave birth to three children while married to a very talented but unstable (professing) Christian man. He left her for a younger, more attractive co‑worker in what looked to me (and to the rest of the world) like the stereotypical male mid-life crisis. It played out like the cliché of all romantic clichés, frankly.
It looked embarrassing. It probably was. I actually liked the departing father a great deal, and was deeply disappointed when I heard about what he had done and what had become of his family.