Is the wife sinful for keeping silent about her husband's adultery with the maid, and what is the husband's punishment for this act?

Adultery is one of the gravest sins, and it is not permissible for a Muslim to commit it. A woman's silence and consent to her husband's act of adultery in her home is a sin and an aiding in disobedience. She must repent to Allah and show remorse. As for the perpetrator himself, he should be shielded (his sin covered), and his matter is subject to the will of Allah. The wife should seek forgiveness for him, show him mercy, and giving charity on his behalf is preferable.