What is the ruling on repeated adultery due to a wife's disobedience (nushuz) and the inability to marry a second wife? Is repentance obligatory, and what is its expiation?

You must hasten to sincere repentance from adultery, by contemplating its grave danger, accompanying the righteous, abandoning corrupt environments, striving in supplication and remembrance, and fasting frequently if marriage is not possible. There is no need for stoning or ending one's life; sincere repentance between the servant and his Lord is sufficient. If the wife is disobedient (nashiz), begin with admonition and reminding her of Allah, then forsake her in bed. If she does not desist, then strike her a non-injurious blow. If she continues in her disobedience, then divorce her and marry someone else, and seek Allah's help in maintaining chastity. If marriage is not possible, then you must strive for chastity, so that you do not incur Allah's wrath and punishment.