When he spoke to her, it was with averted eyes from which the old love light seemed to have gone out. He absented himself from home; and when there, avoided her presence and that of her child, without excuse. And the very spirit of Satan seemed suddenly to take hold of him in his dealings with the slaves.

By this point in the story, Armand has realized what Désirée still has not: their son is Black. The sunnier, gentler approach to running his household and plantation disappears, and Désirée becomes wretched because she cannot explain the change. That Armand refuses even to explain, to offer an excuse that would ease her mind, or to speak honestly in any way reveals what he really thinks of the wife he claimed to love devotedly. She is no more deserving of explanation or consideration than a child or enslaved person. His aloof cruelty marks him as an essentially arrogant man. 

He thought Almighty God had dealt cruelly and unjustly with him, and felt, somehow, that he was paying Him back in kind when he stabbed thus into his wife’s soul. Moreover he no longer loved her, because of the unconscious injury she had brought upon his house and his name.

These sentences describe the scene in which Armand tells Désirée to leave their home and return to her parents’ home. Something of his arrogance is captured in his self-centered, punitive leave-taking of his wife, whose son he no longer considers his. Yet her capacity to forgive and love this petty, angry man is also clear in this exchange. Even as she leaves, “like one stunned by a blow,” she pauses and hopes that he will call her back. His silence is “his last blow at fate” and it is the act, or lack of one, that drives his wife to her death.