1 Corinthians 7:10-11, 15

But for those who are married, I have a command that comes not from me, but from the Lord. A wife must not leave her husband. But if she does leave him, let her remain single or else be reconciled to him. And the husband must not leave his wife.

(But if the husband or wife who isn’t a believer insists on leaving, let them go. In such cases the believing husband or wife is no longer bound to the other, for God has called you to live in peace.)