Hasan al-Basri (may Allah have mercy on him) said: "It is not permissible for a Muslim to marry a woman who is a fornicator or who keeps a secret lover."
Hadith Referenceسنن سعید بن منصور / كتاب النكاح / 1992
Hasan al-Basri (may Allah have mercy on him) said: "If a woman does such a thing while living with her husband, then he should leave her, and not keep her with him."
Hadith Referenceسنن سعید بن منصور / كتاب النكاح / 1993