Hoover structures It Ends With Us by paralleling two timelines in protagonist Lily Bloom’s life. In doing so, she persuades readers to compare and contrast Lily’s character as a fifteen-year-old girl and a twenty-five-year-old adult. These eras feature separate romantic relationships, which Hoover also juxtaposes.

Though her adult timeline is chronologically later, it is where Hoover begins the novel, with Lily meeting Ryle. When Ryle appears, he is noticeably angry, “on the verge of a breakdown” kicking a “marine-grade polymer” chair repeatedly. Lily even draws a line between Ryle and her abusive father in the opening pages: “I once watched my father back over an outdoor patio made of marine-grade polymer, and it practically laughed at him.” This comparison is an immediate red flag, as we soon learn Lily’s father was abusive.

Lily’s first conversation with Ryle confirms that, though she is attracted to him, entering a relationship would be a terrible idea. He only wants a one-night stand, but she seeks something serious. In this opening scene, Lily fights between her sexual and emotional response to Ryle and her rational understanding that a relationship between them is doomed. Other warning signs arise, such as when Ryle forcibly picks up Lily at Allysa’s birthday party and drags her into his bedroom and when Allysa seems hesitant about the prospect of Lily dating her brother.

On the other hand, Ryle’s character develops into a seemingly ideal romantic partner. He sends her flowers, eagerly meets and charms her mother, and enthusiastically marries Lily in Las Vegas. Their blissful union comes crashing down when Ryle becomes violent toward Lily. After each incident, Lily experiences a wide range of emotions, from guilt to hatred to love.

Hoover characterizes Lily as a woman who never thought she would end up in an abusive relationship. She witnessed her father’s violence toward her mother, but she still struggles to make what her teenage self considered a “simple” decision: to walk away immediately if a man becomes abusive. After Ryle pushes Lily down the stairs and reveals he killed his brother when they were children, Lily realizes she “didn’t leave. And now, here I am with bruises and cuts on my body at the hands of the man who is supposed to love me.”

Despite this insight, she remains in denial, though, thinking: “Yes, he screwed up last night. But he’s here, and he’s trying to make me understand.” She repeatedly convinces herself: “Our love is strong enough to get us through this.” She assures him, repeating his statement from the novel’s first chapter, that “there is no such thing as bad people.”

Lily wants to believe that her marriage is different from her parents' marriage, that Ryle is different from her father, and that she is not her mother. Indeed, as Hoover admits in the Author’s Note: “Every situation is different.” Hoover describes Lily’s thought process to subvert the common judgment that leaving an abusive relationship is an easy or automatic decision.

Not only does Lily act against what readers think she should do, she even proves her young self wrong. The teenage Lily timeline is introduced through journal entries she reads from when she was fifteen, providing a useful lens through which the reader can view her adult struggles with domestic abuse and a purposeful comparison between Ryle’s character and Atlas. Through her diary entries, readers get a glimpse of a more naïve but headstrong Lily and understand the serious violence she had to witness growing up, which informed and molded her adult attitudes.

The other key feature of the diary entries is the...