On a night out with his two best friends, Bobby and Danny, Jon sees Barbara Sugarman, a young Jewish woman from a more affluent background. Although she finds him interesting, she declines his offer for a one-night stand. He tracks her down on Facebook and invites her to lunch. There is mutual attraction, but Barbara insists on a long-term courtship, which proceeds for over a month without sex.
She encourages Jon to take night classes to get an office job outside the service industry, and Jon indulges her love for romance movies, which he usually dismisses as unrealistic fantasy. They meet each other's families and Jon's parents love her. The two have sex, but Jon is still dissatisfied. He loves Barbara and considers her body perfect, but still finds pornography more satisfying. While she sleeps, Jon watches pornography. Barbara catches him and is shocked. She prepares to leave Jon, but he denies that he watches pornography and claims it was a joke emailed to him by a friend.
Their relationship resumes, with Jon watching pornography primarily outside his apartment, concealing his habit from Barbara. He is caught watching a video on his cell phone before a college class by Esther, a middle-aged woman Jon earlier encountered weeping by herself. Jon politely brushes her off. Barbara continues asserting control, insisting that cleaning his own apartment, a task Jon finds satisfying, is not something she is comfortable with him doing.
Barbara checks the browser history on Jon's computer, confronts him with proof that he has continued viewing pornography, then ends their relationship. Jon tries to return to his old lifestyle, but ends up in a downward spiral. Esther continues reaching out, offering Jon the benefit of her experience. She lends him an erotic video that she believes has a more realistic depiction of sexual relations. He responds by initiating a sexual encounter in her parked car.
She persuades Jon to try masturbating without pornography, but he is unable to. She feels the reason he is more satisfied with watching than having sex is that pornography is a one-sided affair. If Jon wants to lose himself, it must be to another person, a mutual experience. Esther reveals that her husband and son died in a car accident. With her, Jon forms an emotional sexual connection. Jon tells his family about the break-up with Barbara: Jon meets with Barbara and apologizes for lying to her about the pornography.
Barbara says she asked one thing of him and he failed. Jon replies that she asked many things of him and he could not meet her expectations. As she tells him to never contact her again, he sees how shallow she is and realizes he is better off without her. Jon begins dating Esther.
Even though she is considerably older and neither has any interest in getting married, Jon believes he really understands Esther and that they can get emotionally lost in each other.