'Unfaithful' in the Bible

{Do we not all have} one father? Has not one God created us? Why [then] are we unfaithful {to one another}, profaning the covenant of our ancestors?

Judah has become unfaithful, and a detestable thing was committed in Israel and Jerusalem. Indeed, Judah profaned the Holy Place of the LORD, which he loves, and married a daughter of a foreign god.

Yet you ask, "For what reason?' Because the LORD acts as a witness between you and the wife of your youth, because you were unfaithful to her, your partner, the wife of your covenant.

Did he not make them one? And the vestige of the spirit remains in him. And why did he make them one? He was seeking godly offspring. So guard yourselves in your spirit, and don't be unfaithful to the wife of your youth.

"Indeed, the LORD God of Israel says that he hates divorce, along with the one who conceals his violence by outward appearances," says the LORD of the Heavenly Armies. "So guard yourselves carefully, and don't be unfaithful."