Symbolism, Imagery, Allegory
Before Dianna's death, the parental discord in the Sweetwine household was at an all-time high. The book opens on a scene in which they fight loudly, and you get the sense from the way that they argue that they've been unhappy in their marriage for a while.
It's no coincidence, then, when the sky begins to fall. (Well, okay, it's technically the ceiling.) In the weeks before Dianna dies, the rainy season leads to a leaky roof. "It's pretty much raining inside as well as outside the house," Noah says. "There are pans and pots and buckets everywhere." (5.94)
Around the same time, Mr. Sweetwine has a dream. "Your mother was walking through the house, and as she did, everything fell off the shelves and from the walls: books, pictures, knickknacks, everything," he tells Noah. "All I could do was follow her around the house and put everything back in place." (5.151) And what do you know, it turns out Dianna's a homewrecker, not just in that dream, but in real life: she's having an affair with Guillermo Garcia.
Not for nothing, when Mr. Sweetwine finally starts healing from his grief at the end of the story, he decides to move on by literally moving out of the house. This time around, he wants to live on a houseboat (!) called The Mystery. Um, okay. But it's cool, because his late wife had always told him to "embrace the mystery"—it was their little catchphrase. Hey, better late than never.