I would like to know the Islamic legalities of a Faskh divorce sought by the woman in the case her husband is being held in prison.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

The presence of the husband is a condition for the Khul’ to take place. On the other hand, a wife should not ask for Khul’ unless there is a sound reason for doing so, like when the husband does not fulfill the rights of his wife voluntarily and without being forced or imprisoned. Indeed, the Prophet said: “The women who seek Khul’ are the hypocrites.” [Ahmad, An-Nasaa’i, while Assayooti classified it as week]

As regards the wife asking to be separated from her imprisoned husband, then the majority of the jurists are of the view that it is not permissible to separate them, no matter how long her husband stays in prison. However, the Maaliki School of jurisprudence is of the view that it is permissible to separate a wife from her imprisoned husband if she asks to be separated and she claims to be harmed after the husband spends at least a year in prison.

It seems that the view of the Maaliki School of jurisprudence is closer to the objectives of the Sharee’ah in achieving benefits and ward off disadvantages, provided that she is really harmed.

Therefore, a wife who has an imprisoned husband and feels that she cannot stay without intimate relationships with her husband and fears temptation, then she can ask to be separated and ask for the invalidation of her marriage, then the Muslim judge will study her case and remove harm off her.

However, if she does not mind and is not harmed by her husband's imprisonment, then it is better for her to be patient and seek reward from Allah for that and wait until Allah makes a way out for her husband. The Prophet said: “Any woman who seeks divorce from her husband without a sound reason, the smell of Paradise is forbidden for her.” [Abu Daawood, At-Tirmith, An-Nasaa’i and Ibn Maajah]

Allah knows best.