What is the ruling of Sharia on a man who was deceived after the marriage contract, where a woman was presented to him, but he married another?

If a man proposes to a woman, and then is married to another, while believing that she is the one he proposed to, then the marriage is void (batil (definition)), because the acceptance was directed towards someone other than the one from whom the offer originated. This is the view of the Hanafis, Malikis, Shafi'is, and Hanbalis.

Imam Ahmad stated that in such a case, the couple should be separated. The sadaq (dowry) is to be paid by the guardian of the wife who was deceived. Any child born from this union is attributed to the man if she has given birth to one. However, if the woman knew that she was not the intended wife and that she was forbidden to the man, yet she allowed him access to herself, then she is not entitled to any sadaq, because she is a willing adulteress. But if she was ignorant of the situation, then she is entitled to the dowry, which can be reclaimed from the one who deceived her.