Aśauca-vidhi (Rules of Impurity) within Śrāddha-kalpa — Chapter on Testing/Selecting Brahmanas and Honoring the Atithi
नार्हतस्तावपि श्राद्धं द्विजो यश्चैव वार्धुषी / स्त्रियो रक्तान्तरा येषां परदारपराश्च ये
nārhatastāvapi śrāddhaṃ dvijo yaścaiva vārdhuṣī / striyo raktāntarā yeṣāṃ paradāraparāśca ye
In the śrāddha rite, a twice-born who lives by interest is not fit either. Those whose wives are in their courses (in impurity), and those devoted to another’s wife—these too are unfit.