What is the ruling on one who writes a statement acknowledging that if he marries another woman while his current wife is still his wife, she will be divorced with a final divorce from which there is no taking back?

Question:
May Allah the Exalted reward you with good. This questioner says: A disagreement arose between me and my wife regarding plural marriage, and I wrote a statement as a settlement acknowledging that if I marry another woman while she is my wife, I will divorce her with a final divorce from which there is no taking back. My intention with this phrase is that I will divorce her and will not take her back until her waiting period ends, and I do not intend three divorces, because I know that three divorces are not permissible. The question is: My wife, by the grace of Allah, accepted plural marriage, and after that, is this condition dropped or not?

Answer:
If a woman conditions upon her husband that he not marry another woman while she is his wife, and she conditions this upon him in the contract on the day he contracts with her, conditioning that he not marry another woman while she is his wife, this condition is valid, but it does not make it forbidden for him to marry. He may marry a second, third, or fourth wife, and she has the choice. If she wishes, she remains, and if she wishes, she annuls the marriage. She has the choice. As for the condition after the contract, it is not binding and is not valid. Yes.