Is it permissible for a woman a man is going to marry to stipulate that he divorce his first wife with the third and final divorce, to ensure she cannot return to him?

It is not permissible for a woman to stipulate the divorce of her co-wife or another woman for a man to marry her. If a man divorces his wife and her waiting period ('iddah (definition)) ends, he cannot divorce her again because the marital relationship has ceased, and she cannot return to him except through a new contract. In this case, the man can inform the woman he is proposing to that his previous wife has become irrevocably separated from him, and he cannot divorce her. It is permissible for a woman to stipulate to a man that he not marry another woman, and this is a valid condition according to some scholars, and it is the view of Imam Ahmad. If the husband agrees, she has the right to annul the marriage if he violates the condition and marries another woman during their marriage.