Does a wife sin by forsaking her husband in bed, especially after discovering his adultery, and how should she deal with him given her fear for herself?

The husband's leniency in conversing with, flirting with, and meeting non-mahram (definition) women is a transgression and disobedience. Greater than this is adultery (zina), which is a path that leads to immorality. The husband must repent sincerely and abandon these sins. He may resort to polygyny if he needs it to keep himself chaste.

However, the wife erred by refusing her husband's bed. It is obligatory for her to respond to him unless there is a legitimate excuse or fear of harm, due to the Prophet's (peace and blessings be upon him) saying: "If a man calls his wife to his bed and she refuses, and he spends the night angry with her, the angels curse her until she wakes up."

Even if his adultery is proven, it does not justify refusing his bed, and her fear is merely an illusion that holds no weight. Accusing the husband of adultery without proof is not permissible, and the default assumption for a Muslim is blamelessness. The wife should be an aid to him in repentance and abandoning these acts.