Frédéric and Rosanette settle into a cozy domestic life. Frédéric believes she looks different, but he cannot pinpoint why. He learns that Arnoux is being taken advantage of by a woman from his factory, that his factory has closed down, and that he and Madame Arnoux are nearly estranged. Arnoux visits Frédéric one day and asks him to visit their home again. As Frédéric makes his way there, he runs into a man named Compain, who asks him cryptically if he’s a member of the “calf’s head.” When he arrives, Arnoux is not home. He renews his love for Madame Arnoux, and they kiss. Rosanette, who has followed him there, sees them. At home, Frédéric is so angry at her intrusion that he nearly hits her, but he stops when she reveals that she’s pregnant. Frédéric helps her pay off a debt to Mademoiselle Vatnaz, which she claims is the last owed.
Frédéric becomes annoyed by everything Rosanette does and more and more enchanted with Madame Dambreuse. He is bored by the conversation that goes on at her parties, but he vows to make her his mistress. He visits her frequently and flatters her constantly. One day, she gives in, and Frédéric feels like a new man, finally a true part of society. As he walks home, he runs into Deslauriers, who has been embroiled in controversy and has been shunned by both the Conservatives and the Socialists. Frédéric invites him to stay with him, and Deslauriers encourages Frédéric to run once again for the Assembly. Later, Frédéric attends his first dinner alone with Madame Dambreuse.
When he returns home to Rosanette, he is secretly happy at his deception.
Deslauriers visits Dambreuse and begins working for him. He is in touch with Monsieur Roque, and Frédéric instructs him to lie to Roque and Louise about why Frédéric is delaying marriage. He becomes more infatuated with Madame Dambreuse when he sees her among guests, knowing that he is more intimate with her than anyone else, and society accepts their affair. Madame Dambreuse wants a grand passion from Frédéric, but he soon tires of her gifts and affections. He still wants to raise his position in society through his liaison with her, but he no longer feels the same attraction.
Dambreuse falls ill and dies. Madame Dambreuse is unmoved and happily tells Frédéric that she is the heir to a great fortune. He asks why Dambreuse didn’t leave his fortune to Cecile, who is not his niece but his illegitimate daughter, and Madame Dambreuse insults her endlessly. She asks Frédéric to marry her, and he agrees. He then arranges the entire funeral.
The day after the funeral, Frédéric visits Madame Dambreuse and finds her panic-stricken. She cannot find a will that declares that she is the heir; all she and her lawyer can find is a will naming Cecile as the heir. Frédéric claims he will still marry her and promises that he will love her forever. He tells her he is going to Nogent to prepare for his candidacy.
Meanwhile, Rosanette has given birth to a son. Frédéric visits and guiltily spends several days with her at the maternity home. He gets a letter from Deslauriers telling him that there’s no longer any point in running for the Assembly. When he returns to Paris and Madame Dambreuse, she reads the letter and accuses him of not going to Nogent as he said he would; she had seen Deslauriers, who had been at Nogent for a reason unknown to Frédéric. He tells Madame Dambreuse he has been sick.
Frédéric begins living two lives: one with Madame Dambreuse and one with Rosanette. It turns into a game for him. But one day Madame Dambreuse gets an unsigned letter telling her that Frédéric is living with Rosanette. She trusts him when he says it isn’t true. She asks if he goes to see Madame Arnoux anymore, and he says no. He realizes she knows all about his life while he doesn’t know much about hers. He begins to notice her flaws.
People in Paris have different political viewpoints but most agree about the need to decentralize the government. Courtesans begin hosting gatherings at their homes, which people view as neutral territory. Rosanette follows suit, and Frédéric moves them to a new house and buys new furnishings. Rosanette dreams of being a society lady, and Frédéric realizes she is hoping he will marry her. Although he is angry at the thought, he is still jealous about her old lovers, and he begins hating her.
Rosanette attempts to pay the rest of her debts to Mademoiselle Vatnaz before the latter takes her possessions, but she cannot come up with the funds. Maître Athanase Gautherot, a process server, comes to claim the money and asks for the paintings. Frédéric intervenes, sends the collector away, and vows to find some money. Rosanette tries to cash in some shares Arnoux had promised her, but they are worthless, which infuriates Rosanette. Frédéric vows to see Arnoux.
Frédéric visits Regimbart, who tells him Arnoux sells religious objects. But when he finds the shop, he spots Madame Arnoux and flees. Rosanette is angry and decides to sue Arnoux. But Maitre Gautherot’s collector comes to the house, drunk, and tells them the sale of possessions must go forward. However, he accepts a few francs to tear the corners off the notice he had posted on the door, a notice that named Rosanette. Rosanette is stunned by Mademoiselle Vatnaz’s hatred.
Mademoiselle Vatnaz had met Dussardier when she worked in a business house. Dussardier had covered up her thieving ways, and she fell in love with him. She gave up everything for him, including her political diatribes, and asked him to marry her, but he said no. He finds out about her actions against Rosanette and asks her to drop them, but she refuses. Dussardier leaves her and tries to apologize for her actions to Frédéric. Dussardier claims that he is unhappy now that the revolution is over and things have gotten worse, not better.
Rosanette loses her case against Arnoux, but Deslauriers is certain she can win on a different charge. He recommends her case to Senecal. Deslauriers goes to Nogent, claiming that he is going to buy a law practice, and spends the summer with Roque. He begins angling to win over Louise. He tells the Roques that Frédéric is in love with someone else and has a child. Madame Moreau learns about Frédéric’s impending marriage to Madame Dambreuse.
Rosanette loses her case, but Deslauriers helps her wins her case against Arnoux, thanks to Senecal. When Frédéric goes into her room to congratulate her, she points out the baby, who is very sick. The baby dies. Frédéric hires Pellerin to paint a portrait of the dead child. While he paints, Pellerin reveals that Arnoux, because he is now poorer than ever thanks to Rosanette’s lawsuit, is leaving Paris with his family unless he can procure twelve thousand francs. Frédéric rushes out of the house.
As Frédéric struggles to make a place for himself in society, he makes significant advances in his relationships with Madame Arnoux, Rosanette, and Madame Dambreuse, but all three women begin to overlap and interfere with one another’s relationships, albeit unwittingly. He encounters Madame Arnoux once again, declares his love for her, and they kiss—only to be interrupted by Rosanette. His happy domestic life with Rosanette takes an unexpected turn when he finds out she is pregnant, and his fantasies about a baby with Madame Arnoux prompt him to agree to keep the child. Madame Dambreuse, his newest conquest, brings him further into bourgeois society; but Frédéric fakes his feelings for her by telling her things he’d dreamed of telling Madame Arnoux. He vows to marry Madame Dambreuse, but he is pulled back to Rosanette when their baby dies, and then back to Madame Arnoux when he learns she may be leaving Paris. Although Frédéric takes pleasure in juggling his affairs, the demands each woman makes on him are growing more intense, and the stakes are getting greater.
Frédéric pursues each of his three lovers for a different reason, and the unique needs each woman meets contribute to his inability to choose among them. Rosanette provides a comfortable home life that Frédéric settles into happily, her beauty and sparkling personality a welcome relief from the intense political talk of the people who surround him. Madame Arnoux, though long absent, fuels his romantic imagination—nearly every desire he has for another woman is rooted in his desire for her. She is older than Frédéric and serves as a stable, consistent figure, even as their relationship becomes more fraught. Madame Dambreuse provides the most explicit service: she is his ticket into high society, and the stakes are greatest in his affair with her. Rosanette grows to be a nuisance and Madame Arnoux continues to be troubling, but Frédéric will lose little from casting them aside. However, the life he desires is contingent on Madame Dambreuse’s continued affection. As has proven to be his pattern, Frédéric loses interest in Madame Dambreuse as soon as he conquers her, but in this case he must persevere. When he rushes to pursue Madame Arnoux, he is literally risking his future.
Dussardier, a loyal friend to Frédéric and once an energetic supporter of the revolution, has become disheartened and depressed at the turn France has taken, and his disillusionment in many ways mirrors Frédéric’s. The working class is worse off than ever before, and the bourgeoisie is determined to restore a single power to government. The Republic is floundering, and Dussardier has lost his faith in the workers. It has all been a great disappointment. Frédéric has faced his own disappointments: Rosanette is flirting with financial ruin, and Madame Dambreuse received nothing after her husband’s death. His kiss with Madame Arnoux resulted in nothing. Soon after he speaks with Dussardier, his child will die and he will learn that Madame Arnoux is nearly out of his life forever. French society has been disappointed and disillusioned, and these social unrests are mirrored on a personal level in Frédéric’s own life.
Just as Deslauriers once tried to win over Madame Arnoux in an attempt to take over Frédéric’s life, he now tries to win over Louise. His efforts to become like Frédéric are explicit, and he imitates Frédéric’s manner and speech. This rather creepy appropriation of someone else’s life wins him Louise’s confidence. Although Frédéric no longer seems intent on marrying Louise, Deslauriers’s attempts to woo her are still a betrayal, and we wonder what Deslauriers is up to as he ingratiates himself to the wealthy Roque.