When Homer's poker-playing friends call him "slow," Marge suggests he enroll in an adult education course to sharpen his intellect. However, Homer's friends are teachers, so Homer requests an instructing position himself. He is hired to teach a course on marraige. Enthusiastic at first, Homer soon learns that he does not know how to run a class. As the students begin to leave the classroom, he reveals personal secrets about his marraige. Soon, the class is paying close attention.

Marge finds out that Homer is disclosing private information about her. She tells him that she does not want the public knowing details of their lovelife, but Homer cannot stop himself. When Moe teases Homer about one of the personal secrets right in front of Marge, she kicks Homer out of the house.

Marge refuses to forgive Homer, telling him that he betrayed her trust. Homer takes up temporary residence in Bart's treehouse, hoping Marge will change her mind. Reverend Lovejoy encourages Marge to seek a divorce, but Homer pours his heart out to her and promises that he will never lose her trust again. Moved by Homer's sincerity, Marge forgives him.