1 Corinthians 7:12-13, 15

But to the rest say I, not the Lord: If any brother hath an unbelieving wife, and she is content to dwell with him, let him not leave her. And the woman that hath an unbelieving husband, and he is content to dwell with her, let her not leave her husband.

Yet if the unbelieving departeth, let him depart: the brother or the sister is not under bondage in such cases: but God hath called us in peace.