What is the ruling on a woman paying a private investigator to prove her husband's adultery before a judge, so that she may obtain a larger financial settlement in the divorce?

It is forbidden for a woman to seek divorce or khul' unless there is a valid excuse. The husband's adultery is an excuse that permits this. However, it is not permissible to accuse the husband of adultery without evidence or his confession, and it is not permissible to spy to prove it.

As for the rights resulting from divorce, such as maintenance (nafaqa), compensatory gift (mut'a), deferred dower (mahr mu'ajjal), and child custody wages, they do not differ whether the husband is an adulterer or not. There is no consideration for what secular judiciary decrees regarding fining the husband, and it is not permissible for the woman to take what is not lawful for her according to Sharia.

Divorce does not occur except by the husband divorcing, or his acceptance of khul', or by the ruling of a Sharia judge, or an Islamic center. There is no consideration for divorce granted by the civil judiciary.