Discuss the role of “shame” in the story, "The Lady with the Pet Dog" by Joyce Carol Oates

Joyce Carol Oates’ short story “The Lady with the Pet Dog” recounts Anna’s extramarital affair and how the relationship impacts her at various points.
The theme of shame is inherent in stories dealing with infidelity since readers generally agree that it is morally wrong. Thus, one usually expects people who are unfaithful to feel guilty for hurting their significant others. Anna and her lover do feel some guilt, as evidenced by their mutual agreement to end the relationship before he drives her to Albany. In addition, they limit their affair to private hotel rooms where their relationship can remain concealed from the world.
In the last section of the story, as Anna and her lover talk, she bemoans the loveless state of her marriage, saying there is “no longer even any shame between [her husband and her].” What she means, then, is that she no longer even cares about what he thinks of her and vice versa.
When her lover asks if she still feels shame with him, she fails to respond and prepares to leave—maybe for the last time. In a moment of clarity as she stares at his reflection in the mirror, Anna realizes that she should no longer feel any kind of shame at all—about her affair, about her failed marriage, about what other people think. She realizes that “she did not hate herself any longer; she did not wish to die; she was flooded with a strange certainty, a sense of gratitude, of pure selfless energy.” This shows that shame is a useless emotion that does nothing except rob someone of his or her joy.