Answer:
Dramatic Irony
Step-by-step explanation:
Dramatic irony is a literary device used when the reader knows something or a situation that the characters do not know about but might eventually find out later in the story. This infuses a measure of suspense in the story.
In Kate Chopin's, "The Storm," even though the couple are not aware that each of them was unfaithful, the reader knows this fact well. The reader might also be filled with suspense because he wonders when and how the couple will find out about their respective infidelities.