He does not clarify the reason for his abstinence. An old woman tells Yerma of a history of barrenness in Juan's family. Yerma, realizing that her marriage has lost the only meaning it had for her, strangles her husband in desperation. The structure, plot and characters all serve to embody a theme or a series of themes in a play. There are several other related themes such as honor, gossip, status and money.
Frustration is a major theme.
Yerma's anguish is largely out of her hands. Part of her struggle is her own, and the rest lies with her husband. She wishes she could have children alone, but her wishes run counter to the laws of biology. Juan feels compromised if Yerma goes as far as the fountain to get water for the dinner table. He accuses his sisters of not protecting the honor of the family's name by allowing Yerma out of the house.