Adultery has no place in God’s plan for how He defines marriage. That is why it is clearly spelled out in the Sixth Commandment: “You shall not commit adultery” (Ex 20:14). We can go all the way back to Genesis, and read about the creation of man and woman. It is here that we learn of God’s plan for marriage. We see that Adam and Eve were created in a state of union and love with God.
God blessed them, saying to them: ‘Be fruitful and multiply’ (Genesis 1:28)
That is why a man leaves his father and mother and clings to his wife, and the two become one body (Genesis 2:24).