Is adultery grounds for divorce?
The Greek word translated "sexual immorality" is porneia, and it covers a wide range of sexual misconduct, including but not limited to adultery. The word encompasses many other sins of a sexual nature. Christ's words in Matthew 19:1-12 shed more light on the subject.
The Bible Knowledge Commentary explains that porneia referred to "a relentless, persistent, unrepentant lifestyle of sexual unfaithfulness (different from a one-time act of illicit relations)" (1983, 1985, notes on Matthew 19:1-12). In other words, Christ referred to a pattern of immoral behavior or habitual sin. Other scriptures bring out the fact that there is a difference between sinning and living in sin (1 John 3:8). There is no doubt that sexual misconduct could be grounds for divorce, although there should be hope of saving the marriage if the conduct is not habitual.
Another essential godly principle is forgiveness. One should not abandon a marriage without knowing whether the offending party truly repented of his or her conduct. Considering God's intent for a marriage to last until death, divorce should occur only when there is no repentance or chance for forgiveness and reconciliation.
A Christian's goal should always be to save the marriage. Sadly, in some cases, that simply won't be possible. Christ gave "except sexual immorality" as the "exception clause." If a divorce does occur under these conditions, remarriage is possible without God considering it adultery.
For more information, please read our booklets Marriage and Family: The Missing Dimension and The Ten Commandments.