Matthew 19:9

“If a man takes a wife and marries her, and it happens that she finds no favor in his eyes because he has found some indecency in her, and he writes her a certificate of divorce and puts it in her hand and sends her out from his house,

but I say to you that everyone who divorces his wife, except for the reason of sexual immorality, makes her commit adultery; and whoever marries a divorced woman commits adultery.

But to the married I give instructions, not I, but the Lord, that the wife should not leave her husband