We need to find a moment to talk.
-- Husband (Prologue)

Importance: When the narrator's husband tells her that they need to talk about something important, the narrator becomes convinced that he is going to leave her. The husband's words thus act as the novel's inciting incident. This line catalyzes the temporal shift six days into the past with the subsequent "Monday" section. The husband's words and the narrator's reaction to them also introduce the couple's distorted power dynamic.

I don't have to tell him everything: the couples that last are the ones that keep the mystery alive.
-- Narrator (Monday)

Importance: When the narrator first pulls out her jewelry box, she identifies the box as the container for her secrets. It is indeed the place where she keeps mementos from her past. She does not want her husband to discover its false bottom because she believes it is important to conceal certain information from him. The line...