What is the legal ruling, and what must a husband do concerning his wife who confessed to infidelity during the engagement period and that she is not a virgin? Is divorce the solution in this case?

If the wife's claim of repentance after an illicit relationship is true, her word should be accepted. If her situation becomes upright, he should keep her and treat her well, and she should be removed from the aforementioned workplace. However, if she shows neglect and does not benefit from advice, it is preferable to divorce her, as stated in Ibn Qudamah's rulings on divorce. The husband must raise his family upon faith and obedience to Allah and protect them from trials, in fulfillment of Allah's saying: "O you who have believed, protect yourselves and your families from a Fire."