Shaykh al-Islām—may Allah have mercy on him—was asked:

A man had a wife with whom he had sons and daughters, and he married another woman. He then drew up a written authorization for his new wife, saying, “Whenever I take back the mother of my children, the power to divorce her will be in your hands,” and authorized her to divorce the first wife for a period of ten years. He has since divorced the wife who held this authorization. Is the authorization valid? If it is valid, does divorcing the appointed agent revoke it?

He—may Allah have mercy on him—answered:

Praise be to Allah. Some may suppose that the authorization in this case remains in force, reasoning that if a husband appoints his wife as his agent in a sale or a similar transaction and then divorces her three times, the divorce does not revoke her authorization, as the jurists have stated. But these are not the same case. The correct view in the case presented is that the divorce revokes the authorization. Here, he was not seeking to divorce the first wife and appointing someone else to act on his behalf, as someone wishing to sell his possessions appoints an agent. Rather, his purpose was to give this wife herself the power to divorce the other, placing the other wife’s marital status in her hands: if she wished, the other would be divorced; if she wished otherwise, she would not divorce her. He stipulated for her that the other wife’s marital status would be in her hands, so that the other could remain his wife only with her consent.

The intended meaning is: “I will not marry her without your consent.” This means: “I will not keep both you and her as wives,” because a woman dislikes having a co-wife, which may interfere with the rights conferred by the marriage contract, such as the allocation of time and the like. Once he has divorced her three times, however, she no longer has any right to a share of his time