How can a husband ask his wife for his lawful right to conjugal relations, while taking into account that this might conflict with her acts of worship, her voluntary fasting, and her night prayers?

If a man is blessed with a righteous wife who helps him in obedience [to Allah] and in raising children, he should cherish her and encourage her. She, in turn, must obey her husband in matters that do not involve disobedience [to Allah]. Allah has forbidden a woman from observing voluntary fasts except with her husband’s permission, so that fasting does not prevent her from fulfilling some of his rights. Therefore, a husband has the right to prevent his wife from observing a voluntary fast if he needs her, and there is no sin upon him for doing so. As for the nights of Ramadan, Allah has permitted a husband to enjoy intimacy with his wife. If he needs her, she is not allowed to refuse him; otherwise, the angels will curse her until morning. While a woman's eagerness for acts of worship is beautiful, she must not fall short in fulfilling her husband's rights.