Al-Bukhari reported in his Sahih (no. 250) that ‘Aishah said: “The Prophet (peace and blessings of Allah be upon him) and I used to bathe from one vessel.”
Al-Hafiz said in al-Fath: “Al-Dawudi interpreted this to mean that it is permissible for a man to look at his wife’s ‘awrah and vice-versa. This is supported by the report narrated by Ibn Hibban via Sulayman ibn Musa, who was asked about a man looking at his wife’s private parts. He said: ‘I asked ‘Aishah, and she referred to this hadith.’ This is evidence in this matter. And Allah knows best.”