The Prophet said: "A woman may not fast a day - other than in the month of Ramadan - while her husband is present, except with his permission."
Jami` at-Tirmidhi Book 8, Hadith 101
← Previous Hadith The Prophet said: "When one of you is invited (to a meal) and he is fasting, then let him said: 'Indeed I am fasting.'"

Jami` at-Tirmidhi Book 8, Hadith 100 Next Hadith → "I would not make up what was due upon me from Ramadan except in Sha'ban, until the Messenger of Allah died."

Jami` at-Tirmidhi Book 8, Hadith 102