"Unmailed, Unwritten Letters" by Joyce Carol Oates is a short story that focuses mainly on the psychological state of the narrator. Although there are a series of events alluded to in the story, they serve mainly as pretexts for character analysis. Despite the narrator writing the unmailed (and possible unwritten) letters of the title, we do not get a sense of outward directed communication but rather the letters as pretext for the narrator's own ruminations about her psychological state and emotions.
The basic plot is simple. The narrator is married to Greg. She is unable to have children. She has been having an affair with Mr. Katz (also referred to as X). Mr. Katz has a wife and a daughter, Marsha. Marsha seems to be aware of the affair. The narrator has two nightmares, one envisioning her own suicide and the other X's death in a car accident. Next, Marsha tries to commit suicide. X asks the narrator for a ride to the airport, so he can be with Marsha and his wife. The narrator and Mr. Katz make love, and then he returns to his family.