Is it permissible for a woman to stipulate in the marriage contract that her husband not marry another woman, based on the prevailing custom that a man is content with one wife? And is this condition valid based on the prophetic tradition: "Indeed, the most worthy of conditions to be fulfilled are those by which you have made sexual intercourse lawful"?

A wife's stipulation to her husband that he not marry another is a valid and permissible condition. If the husband violates this condition, his wife has the right to annul the marriage and receive all her rights, as reported from Umar, Sa'd ibn Abi Waqqas, and Amr ibn al-Aas (may Allah be pleased with them). This view has been supported by Imam Ahmad, Ibn Taymiyyah, Ibn al-Qayyim, Ibn Uthaymeen, al-Fawzan, and other scholars, who cite the hadith: "The conditions most worthy of fulfillment are those by which you make intimate relations lawful," and the hadith: "The believers are bound by their conditions." The annulment of the marriage is at the wife's discretion; she may choose to annul it, or she may waive the condition and accept what the husband has done.