How is it that a wife does not have the right to know about her husband marrying another, when tranquility, affection, and mercy have been made the foundation of marriage, and how is it that this would not forfeit a right of hers?

Polygyny is a right guaranteed to a man by the Sharia, provided he is capable of being just. The Sharia does not require the husband to inform his wife of his marriage to another woman. A husband may conceal his second marriage to achieve a great legitimate objective, which is to preserve the good companionship between them. Concealing a permissible matter for a specific benefit is permissible, and not everything a person conceals is reprehensible, as the Prophet, peace and blessings be upon him, said: "Seek help in achieving your needs through concealment, for every person blessed with a bounty is envied." The wife does not have the right to demand a divorce merely because her husband married another.