What is the ruling on a man marrying secretly without the knowledge of his first wife, and what are the implications of that for the second wife?

Marriage is valid if its conditions are met: offer and acceptance, the guardian's permission, and the presence of witnesses. Its validity does not require public announcement; rather, that is a recommended act. Nor does it require the knowledge or permission of the first wife. The husband must be just between his wives in terms of lodging and financial support, even if they live in different cities. The wife has the right to waive her right and to retract her waiver whenever she wishes.