The ruling on a woman who embraces Islam while her husband remains in shirk (associating partners with Allah)

Q: And as for the questioner’s statement: “A man has sisters who married disbelieving men. When he was guided, he wanted to call them to tawhid (the oneness of Allah), but his sisters refused him, and their husbands did not respond to him. Should he separate his sisters from their husbands, or what should he do?”

A: If they are Muslim women, the marriage is invalid, and it is obligatory for him to separate his sisters from them; this is required of him. If they are in an Islamic land, it is obligatory for its ruler to separate them from their disbelieving husbands. However, if they are disbelieving women along with their husbands, such as Jewish, Christian, or polytheist women, their marriages are valid. If they then embrace Islam, it becomes forbidden for them to remain with them while they are not Muslims; because of the saying of Allah the Exalted: [Al-Mumtahanah: 10]. They must separate from their disbelieving husbands, unless the husband embraces Islam during the waiting period, in which case he is her husband. Likewise, after the waiting period, according to the correct opinion, if she has not married another, he may return to her, just as the Prophet’s (peace and blessings be upon him) daughter Zaynab (may Allah be pleased with her) returned to her husband Abu al-As ibn al-Rabi' after he embraced Islam, even though the waiting period had already passed.
And may Allah send prayers and peace upon our Prophet Muhammad, his family, and his Companions.