Mishneh Torah — Positive Mitzvot מצוות עשה, Chapter 219

לישב מוציא שם רע עם אשתו כל ימיו, שנאמר: "ולו תהיה לאישה" (דברים כב,יט).

For a person who made defamatory remarks about his wife to remain married to her for his entire life, as [Deuteronomy 22:19] states: "She shall become his wife. He may not send her away for his entire life."