Cover of Dear Debbie

Dear Debbie

by Freida McFadden


Genre
Thriller, Suspense, Fiction
Year
2026
Pages
320
Contents

Chapter 21

Overview

Harley’s narration reveals that Debbie’s new friend is also Cooper’s mistress, and Harley knowingly cultivated the friendship after recognizing Debbie at Titan Fitness. Cooper presents himself as trapped in a dead marriage, while Harley hopes the affair will be exposed so Debbie will kick Cooper out.

The chapter reframes Harley’s closeness with Debbie as manipulation and raises the stakes of the betrayal: Harley is not merely hiding the affair, but actively positioning herself to replace Debbie.

Summary

Harley narrates after sleeping with Cooper and bluntly acknowledges that she is having an affair with a married man. Harley justifies the betrayal by claiming humans, especially men, are not meant to be monogamous, and frames Cooper’s desire for Harley as biologically inevitable because Debbie is older.

In bed, Cooper tells Harley that Cooper and Debbie are like strangers forced to live together. Cooper says Cooper wishes Cooper did not have to pretend anymore, but Cooper argues that divorce would be difficult because Debbie would take everything and because Debbie is not stable. Harley accepts Cooper’s claims and connects them to Debbie’s recent poisoning of the book club.

Harley then explains how Harley came to know Debbie. Harley saw Debbie check in at Titan Fitness when Cindy at the front desk identified Debbie as Debra Mullen. Because Cooper has no social media presence, Harley admits Harley used real-life reconnaissance to learn more about Cooper and initially meant only to have a conversation with Debbie.

The conversation turned into regular coffee meetings, then a book club invitation, and eventually a close friendship. Harley recognizes that befriending the wife of the man Harley is sleeping with is dangerous and deceptive, so Harley deliberately keeps the friendship secret from Cooper. Harley also admits that Harley may want the truth to surface because Debbie might throw Cooper out, sending Cooper directly to Harley.

As Cooper gets dressed to leave, Harley asks whether Cooper will return the next day. Cooper says Cooper will try but makes no promises, reinforcing Harley’s loneliness as the other woman. Despite acknowledging that affairs with married men have ended badly before, Harley convinces herself that Cooper is different and that soon Debbie will know Cooper belongs with Harley.

Who Appears

  • Harley
    Cooper’s mistress; narrates, justifies the affair, and admits befriending Debbie to study the marriage.
  • Cooper Mullen
    Debbie’s husband and Harley’s lover; claims his marriage is dead but refuses to leave.
  • Debbie Mullen
    Cooper’s wife and Harley’s friend; unknowingly confides in the woman sleeping with her husband.
  • Cindy
    Titan Fitness front desk worker whose check-in screen reveals Debbie’s identity to Harley.
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