What is the ruling on a man who committed fornication with a woman, causing her to become pregnant, marrying her after she marries another man, and after her husband finds out and wishes to divorce her, given that five months of the pregnancy have passed?

The fundamental principle is that the child belongs to the marriage bed (to the husband). A pregnancy discovered after marriage is attributed to the husband and can only be disclaimed through li'an (oath of condemnation). However, if the wife confesses to adultery and does not give birth to the child before the minimum gestation period (six months), then it is ruled that the child is a product of adultery. Marriage between an adulterer and the woman with whom he committed adultery is not permissible unless both have repented. If she is pregnant as a result of adultery, marriage is not permissible until she delivers the child, according to the preponderant opinion. It is not permissible to attribute the child to his biological father from adultery, according to the majority of scholars.