He did not succeed in adapting his face to the position in which he was placed towards his wife by the discovery of his fault.

Instead of being hurt, denying, defending himself, begging forgiveness, instead of remaining indifferent even--anything would have been better than what he did do--his face utterly involuntarily (reflex spinal action, reflected Stepan Arkadyevitch, who was fond of physiology)--utterly involuntarily assumed its habitual, good-humored, and therefore idiotic smile.

This idiotic smile he could not forgive himself.