Q: If a woman makes her to be husband write and sign the nikaah contract with the point that he is not allowed to marry another women whilst they are married, will this ruling apply to him?
A: Shari’ah has given him this right, so she cannot do so. It is an invalid condition. The Nikah to the first wife will be valid but the condition will not carry any weight. If he makes a second Nikah, it will be valid too, without affecting the first Nikah.
Moulana Yusuf Laher