Is it permissible for a woman who is making up for missed fasts in Ramadan to break her fast if her husband desires her, knowing that she informed him before she started fasting, and what should she do if he threatens her with divorce?

Whoever embarks on an obligatory fast, such as making up for missed days of Ramadan, or an expiatory fast (kaffarah), etc., is not permitted to break it, and must complete it. This is supported by what Umm Hani’ narrated, that the Prophet, peace and blessings be upon him, said to her: "It does not harm you if it was a voluntary fast," which indicates that breaking an obligatory fast is harmful and entails sin.

Therefore, it is not permissible for a woman to break her fast of making up for Ramadan days if her husband desires her to do so. She must inform him and seek his approval before beginning the fast if time is not pressing. If she fasts and then her husband desires her, she is not permitted to obey him, even if he threatens her with divorce; for there is no obedience to a creature in disobedience to the Creator.