Jack Linden and Hank Evans are two close friends working as literature professors at a local university, each navigating the complexities of their intertwined lives. One fateful evening, they host a dinner party with their wives, Terry and Edith. However, amidst the chatter and laughter, clandestine truths begin to unravel. During a seemingly innocent trip to fetch beer, Jack and Edith are discovered to be entangled in a romantic affair, a revelation that complicates the evening’s carefree atmosphere. Upon returning home, a drunken Terry fiercely accuses Jack of deceit, insinuating that the beer run was merely a sham. Jack vehemently denies any wrongdoing but is temporarily ousted from his own home, a moment thick with tension and accusations. The following morning, however, tenderness returns as Terry apologizes and vows to curb her drinking, but their two young children, Sean and Natasha, sense the lingering discord between their parents. Jack reassures them that every couple has their disagreements.

As their illicit romance continues in secrecy, Jack and Edith find themselves sneaking away for intimate rendezvous in secluded woods and motels, further testing the fragile bonds of their respective marriages. Meanwhile, Terry, sensing an affair is afoot, begins to question Jack’s loyalty, oblivious to the identity of the other woman. In parallel, Hank, played by Peter Krause, wrestles with his own creative frustrations, attempting to revive his stalled writing career amidst professional disappointments. During a bar encounter, Hank confides to Jack about a lingering love for a woman from his past, igniting a conversation on the confines of marital fidelity. Jack’s probing leads Hank to defend his reasons for staying with Edith, asserting that most men should experience at least one affair.

The strain on Jack and Terry’s marriage intensifies, leading Jack to suggest Terry might be having an affair with Hank, a notion that both repulses and intrigues her. In a twist of fate, she reveals that Hank had made a drunken advance towards her, claiming he no longer loves Edith, yet she rebuffs the idea of betraying her friend. However, a moment of chance leads to Terry and Hank embarking on their own affair. When Jack discovers Terry’s betrayal, she passionately claims he orchestrated the conditions that drove her to Hank. At a celebratory gathering honoring Hank’s poem published in The New Yorker, the tension escalates as their shared secret becomes glaringly evident to both couples.

In a highly charged confrontation at home, Jack confesses his love for Edith, shattering Terry. As she confronts the stark reality of their situation, she takes a stance of emotional resilience, moving to clean up the remnants of their fractured relationship instead of seeking solace with Jack. The next morning, the couple’s children sense the upheaval and voice their fears about their family’s future, further weighing on Jack. Determined to save their marriage, Jack expresses his unwillingness to leave his wife.

That evening, Terry reveals her knowledge about Edith planning to confront Hank regarding their affair, provoking Jack to pay a visit to Hank and the seemingly unperturbed couple. Upon arrival, Jack finds Hank nonchalant, a sentiment that raises Jack’s suspicions about Hank’s awareness of the affair. After a brief exchange, Jack confronts Hank, only to discover his friend had known about the infidelity all along. The emotional tension culminates in a bittersweet farewell between Jack and Edith before he leaves the house. The sorrowful aftermath hits Hank when Edith informs him she plans to stay with her mother, revealing the fracture in their relationship is not merely forgiveable, but unbridgeable. The cycle of affairs, love, and heartbreak leaves both couples grappling with the profound consequences of their choices, forever altering their lives.