It was narrated from Ibn 'Abbas that:
a man declared Zihar upon his wife, then he had intercourse with her before offering expiation. He came to the Prophet (ﷺ) and told him about that. He said: "What made you do that?" He said: "I saw her ankles in the moonlight, and I could not control myself, and I had intercourse with her." The Messenger of Allah (ﷺ) smiled and told him not to go near her until he had offered expiation.
English reference: Vol. 3, Book 10, Hadith 2065
Arabic reference: Book 10, Hadith 2143