Is the condition in the marriage contract that stipulates the wife's right to divorce if her husband marries another, valid throughout the entire period of the marriage?

If a woman stipulates in the marriage contract that her husband must not marry another, the correct view is that this condition is valid and binding on the husband. Should he marry another woman, his first wife has the right to separate from him. This ruling is based on the Almighty's saying: "O you who have believed, fulfill [all] contracts," and the hadith: "Muslims are bound by their conditions, except for a condition that makes a forbidden thing lawful or a lawful thing forbidden." This has been the fatwa of Sheikh al-Islam Ibn Taymiyyah, Ibn al-Qayyim, Imam Ahmad, and a number of Companions and Tabi'in.