Is it permissible for a woman to marry another man with the intention of making herself lawful again for her former husband, and is it permissible for her to seek divorce from him after consummation or through khulʿ, in order to return to her husband and children?

If a man divorces his wife thrice, she does not become lawful for him until she marries another husband in a marriage of genuine desire, not one for analysis (making her lawful for the first husband). This is based on the Almighty's saying: "And if he has divorced her [for the third time], then she is not lawful to him afterward until she marries another husband." Also, the Prophet (peace be upon him) cursed "the one who makes lawful [for another] and the one for whom it is made lawful."

The forbidden 'tahlil' (making lawful) is that which occurs by agreement between the divorcer, the wife, and the one making her lawful, or if the one making her lawful alone intends it. Similarly, if the wife alone intends it, which is the more valid view, because by doing so she is circumventing the Sharia (definition) and deceiving the second husband.

Shaykh Al-Islam Ibn Taymiyyah held the view that the intention of any of the parties (the first husband, the second husband, or the wife) for 'tahlil' invalidates the marriage, because the wife would then be mocking the verses of Allah, deceiving the man, and not upholding the limits of Allah.

Shaykh Ibn Uthaymeen held the view that any intention of 'tahlil' from any of the parties (the husband, the wife, or the guardian) invalidates the contract, because actions are judged by intentions, and because a marriage with such an intention does not fulfill its purposes of affection and mercy.