Is a wife divorced if she concealed a physical defect before marriage, and what is the ruling on someone who conditioned his wife's divorce upon her spending a night outside the home without his permission, and does the divorce take effect if she does so?

If the wife is religious and of good character, and you have been blessed with children from her, then hold on to her, be patient, and treat her with kindness. If you are capable of being just and bearing the expenses of marriage, then you may marry another, for Allah, the Almighty, says: "Then marry those that please you of [other] women - two or three or four. But if you fear that you will not be just, then [marry only] one or those your right hand possesses. That is more suitable that you may not incline [to injustice]."

As for conditional divorce, if it was merely an inner thought and you did not utter it, then nothing is incumbent upon you, for the Prophet, peace and blessings be upon him, said: "Indeed, Allah, the Exalted, has overlooked for my Ummah what they think to themselves, so long as they do not act upon it or speak of it." However, if you uttered it, then the divorce occurs upon the fulfillment of the condition, and the wife's knowledge of the divorce's occurrence is not a prerequisite.