There's only one Biblical reason.
Jesus taught but one exception for divorce and remarriage.
Matthew 5:31-32: It hath been said, Whosoever shall put away his wife, let him give her a writing of divorcement: But I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causeth her to commit adultery: and whosoever shall marry her that is divorced committeth adultery.
Matthew 19:3-9: The Pharisees also came unto him, tempting him, and saying unto him, Is it lawful for a man to put away his wife for every cause? And he answered and said unto them, Have ye not read, that he which made them at the beginning made them male and female, And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh? Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder. They say unto him, Why did Moses then command to give a writing of divorcement, and to put her away? He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so. And I say unto you, Whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery.
Many of the Jews believed one could put away his wife for any cause and they used the commandment in the Law of Moses to support their practice.
Deuteronomy 24:1-2: When a man hath taken a wife, and married her, and it come to pass that she find no favour in his eyes, because he hath found some uncleanness in her: then let him write her a bill of divorcement, and give it in her hand, and send her out of his house. And when she is departed out of his house, she may go and be another man's wife.
"Uncleanness" - blemish, fault, shame, disgrace. Some of the Jews divorced their wives if they were unable to bear children, had a cross disposition, if she was a poor housekeeper, and many other reasons. Whatever the excuse given for divorce by the Jews, this bill of divorcement was written not for adultery or sexual unfaithfulness.
Leviticus 20:10: And the man that committeth adultery with another man's wife, even he that committeth adultery with his neighbour's wife, the adulterer and the adulteress shall surely be put to death.
Those that committed adultery were put to death. The Jews were going to stone the women caught in the act of adultery.
John 8:3-5: And the scribes and Pharisees brought unto him a woman taken in adultery; and when they had set her in the midst, They say unto him, Master, this woman was taken in adultery, in the very act. Now Moses in the law commanded us, that such should be stoned: but what sayest thou?
In this gospel dispensation under the Law of Christ, can we put away our wives for every cause? No, there is only one biblical reason.
Matthew 19:9: And I say unto you, Whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery.
Fornication - a general term for "illicit sexual relations."
Strong's Exhaustive Concordance - "harlotry including adultery and incest."
Vines Expository Dictionary - "illicit sexual intercourse, stands for and includes adultery."
Example of fornication:
I Corinthians 5:1: It is reported commonly that there is fornication among you, and such fornication as is not so much as named among the Gentiles, that one should have his father's wife.
A man having his father's wife - incest. She could also be called an adulteress.
Acts 15:20: But that we write unto them, that they abstain from pollutions of idols, and from fornication, and from things strangled, and from blood.
A general term for all unlawful sexual relations before and after marriage. Fornication includes all illicit sexual relations with another: fornication before marriage, adultery after marriage, incest, homosexual relationships, etc.
Jesus' exception is not a commandment to do, but an allowance if only absolutely necessary. Forgiveness, reconciliation ought to be in order first.
The rule is one man and one woman for life.
Mark 10:10-12: And in the house his disciples asked him again of the same matter. And he saith unto them, Whosoever shall put away his wife, and marry another, committeth adultery against her. And if a woman shall put away her husband, and be married to another, she committeth adultery.
If you put away a sexually innocent husband or wife and marry another you commit adultery. Jesus' teachings concerning divorce and remarriage protects the innocent party.
Jesus spoke again to the Pharisees (the Jews who believed they could put away a wife for every cause) of the rule.
Luke 16:14-18: And the Pharisees also, who were covetous, heard all these things: and they derided him. And he said unto them, Ye are they which justify yourselves before men; but God knoweth your hearts: for that which is highly esteemed among men is abomination in the sight of God. The law and the prophets were until John: since that time the kingdom of God is preached, and every man presseth into it. And it is easier for heaven and earth to pass, than one tittle of the law to fail. Whosoever putteth away his wife, and marrieth another, committeth adultery: and whosoever marrieth her that is put away from her husband committeth adultery.
He had already spoke the exception.
Other scriptures which some wrest to promote the false doctrine ofÂ "no exception."
Romans 7:1-4: Know ye not, brethren, (for I speak to them that know the law,) how that the law hath dominion over a man as long as he liveth? For the woman which hath an husband is bound by the law to her husband so long as he liveth; but if the husband be dead, she is loosed from the law of her husband. So then if, while her husband liveth, she be married to another man, she shall be called an adulteress: but if her husband be dead, she is free from that law; so that she is no adulteress, though she be married to another man. Wherefore, my brethren, ye also are become dead to the law by the body of Christ; that ye should be married to another, even to him who is raised from the dead, that we should bring forth fruit unto God.
Paul's burden here is not the teaching of divorce and remarriage, but the truth that we are no longer bound by the ceremonies and ordinances of the Mosaic Law because we are now married to Christ. (verse 4) Paul used the rule of literal marriage found in the Mosaic Law for comparison's sake. (verse 2-3) The Mosaic Law also proscribed exceptions in Deuteronomy 24:1-2. Paul could not have used the exception but the rule to get the comparison.
Again we see the rule in:
I Corinthians 7:39: The wife is bound by the law as long as her husband liveth; but if her husband be dead, she is at liberty to be married to whom she will; only in the Lord.
However, there may be situations in which a wife must depart from her husband: as in the case of physical danger to her, to her children, etc. (verse 11) In similar situations she must remain unmarried or be reconciled to her husband. There is only one exception and reason for divorce - fornication. Most men or women that leave their spouses today end up having illicit sexual relations with another. The innocent spouse is not under bondage in such cases. (verse 15)
I Corinthians 7:11: But and if she depart, let her remain unmarried, or be reconciled to her husband: and let not the husband put away his wife.
I Corinthians 7:15: But if the unbelieving depart, let him depart. A brother or a sister is not under bondage in such cases: but God hath called us to peace.
The false doctrine of "no exception" is a doctrine of bondage. It puts the innocent person under unnecessary temptations, gives place for the devil to work, and brings people under bondage all their lives thinking they are doing God's service.
Many people who hold to the fanatical "no exception" doctrine also hold to other fanatical ideas such as no musical instruments in the church, no neckties, no coffee, etc.
Serving God is "reasonable service."
Romans 12:1-2: I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.
The Word of God, the gospel of Jesus Christ, stresses over and over the rule of one man and one woman for life. Christ gave but one exception for divorce and remarriage.