WHAT PEOPLE SAY
In some cultures it is even normal for married people, particularly men, to have sex outside of marriage. And many think that marriage does not have to be for life.

WHAT THE BIBLE SAYS
In the Bible, the word adultery usually refers to when a married man or woman voluntarily has sex with someone who is not their spouse (Job 24:15, Proverbs 30:20). Adultery is something disgusting to God. In fact, in the Law that he gave to Israel, adultery was punishable by death (Leviticus 18:20, 22, 29). And Jesus Christ said that his disciples should not commit adultery (Matthew 5:27, 28, Luke 18: 18-20).

WHY IT MATTERS
The adulterer breaks the solemn promise he made to his spouse on his wedding day. In addition, adultery is "sin against God" (Genesis 39: 7-9). The children also suffer, because they could be separated from one of their parents. For all this, the Bible warns: "God will judge fornicators and adulterers" (Hebrews 13: 4).

"Honor marriage, and the married keep one another faithful." (Hebrews 13: 4, New Living Translation

Does adultery put an end to marriage?
WHAT THE BIBLE SAYS
The Bible allows a person to divorce if their spouse has been unfaithful (Matthew 19: 9). The faithful spouse has the right to decide whether to continue with the adulterer or ask for a divorce. This is a personal decision; no one else can decide for him (Galatians 6: 5).

But remember that God sees marriage as a sacred union that should last a lifetime (1 Corinthians 7:39). It bothers him very much that someone tries to divorce for reasons of little importance, such as being bored with the person he married. Therefore, it is not a matter of divorcing for any reason (Malachi 2:16, Matthew 19: 3-6).

"Everyone who divorces his wife, except for sexual immorality, exposes her to adultery." (Matthew 5:32)

Is adultery an unforgivable sin?

WHAT THE BIBLE SAYS
No. In the Bible we read that God forgave men and women, including adulterers, who repented of their sins and abandoned their immoral life (Acts 3:19; Galatians 5: 19-21). These people became friends of God (1 Corinthians 6: 9-11).

An example was King David. He was a married man and slept with the wife of an officer of his army (2 Samuel 11: 2-4). The Bible says that this action of David "seemed evil in the eyes of the Lord" (2 Samuel 11:27). After being rebuked, David repented and God forgave him. Even so, he could not avoid the bitter consequences of his mistakes (2 Samuel 12:13, 14). King Solomon said later: "The man who commits adultery is a total fool, because he destroys himself" (Proverbs 6:32).

WHAT YOU CAN DO
If you have committed adultery, you must ask forgiveness from God and your spouse (Psalm 51: 1-5). Hate adultery, just as God hates it (Psalm 97:10). Flee pornography, sexual fantasies, flirting and anything that might lead you to be attracted to another person (Matthew 5:27, 28, James 1:14, 15).

And if it is your spouse who has been unfaithful, you can be sure that God understands your situation (Malachi 2:13, 14). Ask for comfort and guidance, for the Bible promises: "[God] will sustain you" (Psalm 55:22). If you choose to forgive and not divorce, you both have to make a great effort to rebuild your marriage (Ephesians 4:32).

"Jehovah [...] lets your sin pass," Nathan told King David, who repented of having committed adultery. (2 Samuel 12:13)