Marco Bernardi is another of the novel’s main characters and part of the overarching friend group. He joins this group when he moves in with Richie in 2007 at the start of the novel. He meets Mia at the New Year’s Eve party—launching their romantic relationship—while also becoming acquainted with Adam, Sasha, and Nina Guzman. 

From Mia’s point of view, Marco is a dynamic, engaging person with a similarly interrogative mind. Marco’s individual chapters reveal that he sees himself in a more critical light. When he first begins college, he is “immediately intimated by the pedigree and wealth of his classmates” (23). He often feels awkward around his peers when he first moves to New York City, too, perpetually questioning how they see and think about him. With Mia, however, he feels more comfortable and accepted.

Like Mia, Marco experiences a protracted crisis of identity after the two break up. Since Marco was in love with Mia when he took the job in DC, he did not expect his new job to sabotage their romantic future. Losing Mia and leaving the city he had just begun to call home launches a new phase of self-discovery for Marco. He finds himself pursuing a more traditional life path by working in finance and settling down and raising a family with his new partner, Emily. His chapters parallel Mia’s throughout the novel, in that his internal monologues are often consumed by comparing his past with Mia to his present without her. At the end of the novel, he and Emily have divorced, and it is implied that he will soon act on his feelings for Mia.

Richie Fournier is also a primary character and one of the six main friends. Richie is dynamic, witty, and sarcastic. He is bold and outspoken and often uses his gregarious personality to mask his fraught relationship with drugs and alcohol. 

Everyone likes Richie, but Richie’s chapters reveal how difficult it is for him to feel secure in his friendships while living with a substance dependency. Throughout the novel, Richie goes to rehab and gets sober numerous times. These efforts are often inspired by his relationship with Adam, whom he has been in love with for many years. Richie wants to be better for Adam, but he often despairs that these efforts are not enough, given that the seemingly perfect Adam has already made a life beyond him. 

Like his friends, Richie is round and dynamic, evolving as a result of his challenges and relationships. Adam’s death particularly urges Richie to focus on his sobriety and to value his friendships. After Adam’s funeral, Richie re-commits to his sobriety by refusing a drink at the last minute, showing how far he has come.

Adam Parker is another primary character. The chapters titled with his first name are limited to his perspective and provide insight into his interiority. Adam is primarily connected to the main friend group because he lives with Mia and Sasha in New York for a time and dates Richie on and off for several years. 

Unlike his friends, Adam presents himself in a perfectionist manner. He does everything in his power to be good, helpful, and supportive. He always tries to make the best choice and to create as little conflict as possible. These tendencies originate from Adam’s traumatic childhood: His parents died when he was a toddler, causing him to move in with his aunt, whom he always feared being a burden to. While everyone undeniably likes Adam, over time, the characters become increasingly intolerant of his goodness, insisting he is always trying to prove himself superior. These frustrations sever the majority of the friends’ ties with Adam at the end of Part 5.

Adam’s death at the end of the novel draws the characters back together. Losing Adam makes the friends realize how short life, in fact, is and how valuable their friendships are.

Sasha Karlsson-Lee is another primary character and member of the central friend group. The chapters titled with her name are also limited to her perspective and offer deeper insight into her character. At the novel’s start, Sasha appears to be a self-possessed, no-nonsense character whom others either respect or fear. Adam attributes her reputation to the fact that she is “beautiful, and rich, and dating Theo Wingate, whom most of the women and half the men he knew wanted to fuck” (51). Inwardly, however, Sasha is more insecure. She is easily discouraged, doesn’t take criticism well, and feels dissatisfied with her predictable relationship with Theo. Everything in her life is nominally good and stable, but Sasha perpetually wants more.

Despite her innate instincts toward impulsiveness and exploration, Sasha pursues a more conventional life path. Almost immediately after college, she marries Theo. To her best friend Mia, this path feels like a betrayal: “In the thirteen years they had known each other, Mia had never seen Sasha act so irrationally” (83). This distance between the friends only grows over time. While the women once understood themselves according to their relationship with each other, Sasha begins to feel that Mia’s single, child-free, career-driven life is an affront to her married family life. Meanwhile, Mia feels that Sasha’s relationship and maternity have robbed them of their former connection. 

While Mia does her best to remain respectful of Sasha’s life, Sasha has more difficulty quieting her feelings. She not only sleeps with Mitch Reynolds to escape her numbing relationship with Theo, but she also attacks Mia for wanting to go away together and reminiscing too frequently about their college days. At the same time, Sasha proves herself a round, dynamic character by the novel’s end by admitting her wrongs and making amends.

Nina Guzman is another primary character. She is also a part of the central friend group, although she perpetually feels pushed to the margins of the collective. 

Nina is an awkward, self-conscious character who tries hard to be liked. Mia’s, Marco’s, Richie’s, Adam’s, and Sasha’s chapters reveal that none of them thinks highly of Nina—particularly in the first half of the novel. They see her as disingenuous and exhausting. Worse, they regard her as an easy target, often ridiculing or bullying her to put her in her place. Her situation reflects a darker, more insular side to the friend group.

Despite this perennial emotional abuse, Nina remains desperate to be a part of this group. She invites herself to parties or inserts herself in relationships, eager to belong. Later on in the novel, she and Richie establish a more natural connection.

Theo Wingate is a secondary character. He is a part of the wider friend group when the main characters are in college but primarily features in Sasha’s chapters. He and Sasha begin dating when they are young and end up marrying after they finish school. Mia disapproves of the relationship because she believes Sasha wants a different life. At the same time, “[a]nyone could see that she and Theo were in love—they complimented each other’s terrible jokes and always made a show of predicting what the other one was going to order at a restaurant” (83). 

Despite their overt compatibility, Sasha’s chapters reveal that she is, in fact, bored in her relationship with Theo. Before they marry, Sasha appreciates that Theo is “accommodating and trusting and understanding” but also “wishe[s] they could occasionally get into disagreements and have public fights […] and that when they fucked he would pull her hair hard—like, very hard—without being prompted to” (30). Sasha’s desires for the relationship reveal that she and Theo are, in fact, mismatched, and foreshadow the devolution of their dynamic years in the future. 

Sasha later ends up having an affair with Mitch Reynolds because she is irritated with Theo’s depression after he loses his job. Theo proves himself to be a markedly sensitive person who perhaps tries too hard to be too perfect. As soon as he disappoints this model of the ideal husband and father, Sasha is ready to give up on their relationship.