It’s my understanding that the bible does not forbid a person from divorcing an unfaithful spouse. It’s also my understanding that a divorced person who remarries someone else is committing adultery. What if a person divorces an unfaithful spouse and then remarries someone else? Is this adultery?
In the New Testament divorce is mentioned in Matt. 5:31-32, Matt. 19:9, Mark 10:11-12, Luke 16:18 and 1 Cor. 7:12-14. In every instance the focus is on the person causing the divorce, who is forbidden to remarry, and anyone marrying a such a person is guilty of adultery. Both Matthew references permit divorce due to marital unfaithfulness, where divorce is authorized but not mandatory. And Paul said if an unbeliever wants to divorce a spouse who has become a believer, the believer is not obligated to remain in the marriage. The other passages don’t mention these exceptions.
There is no clear instruction regarding the innocent spouse in a divorce action, but some scholars take the view that neither party can remarry. I believe divorce is a sin, but is not an unforgivable sin. The Lord’s mercies are new every morning, and the only sin that can’t be forgiven is the sin of rejecting the remedy the Lord made for our sins. I also don’t believe it was the Lord’s intention to punish the innocent party in a divorce by making him or her remain single for life. But as Paul said, “That’s my opinion not the Lord’s” (1 Cor. 7:12).