Well, let's start with the bad news: The real-life Nashes ended up dying tragically in a car accident. (Source)

And here's some good news and bad news mixed together: John and Alicia actually got divorced for a while…but then remarried years later. They were together for about sixty years. (Source)

Charles might not have been real—but the actor who plays him, Paul Bettany, is. And after filming was over, he married Jennifer Connolly, the actress who plays Alicia. (Source)