1 Corinthians 7:9

But this I say by way of concession, not of commandment.

Yet I wish that all men were like me. However, each man has his own gift from God, one of this kind, and another of that kind.

But I say to the unmarried and to widows, it is good for them if they remain even as I am.

But to the married I command—not I, but the Lord—that the wife not leave her husband

(but if she departs, let her remain unmarried, or else be reconciled to her husband), and that the husband not leave his wife.

But to the rest I—not the Lord—say, if any brother has an unbelieving wife, and she is content to live with him, let him not leave her.