Is the husband entitled to reclaim the Mahr if he discovers that his wife is not a virgin and that she has informed her family of his suspicions?

The absence of a hymen does not signify a woman's corruption, and it has many causes other than intercourse. If you harbored ill thoughts about her without evidence, you must repent and seek her forgiveness. If you fear a greater harm, then supplicate to Allah for her. The dowry is the wife's right. If virginity was stipulated before the marriage contract and you are not satisfied after discovering otherwise, then you have the right to annul the marriage and reclaim the dowry from whoever deceived you. Marrying a second wife is permissible if you are able to act justly, but deliberation is better to avoid embarrassing the first wife and her family and to prevent ill suspicions.