When discussing what the Bible says about divorce, it is important to keep in mind the words of Malachi 2:16, “I hate divorce, says the Lord God.” Whatever grounds the Bible possibly gives for divorce, that does not mean God desires a divorce to occur in those instances. Rather than asking “is ______ a grounds for divorce,” often the question should be “is _______ grounds for forgiveness, restoration, and/or counseling?”
The Bible gives two clear grounds for divorce: (1) sexual immorality (Matthew 5:32; 19:9) and (2) abandonment by an unbeliever (1 Corinthians 7:15). Even in these two instances, though, divorce is not required or even encouraged. The most that can be said is that sexual immorality and abandonment are grounds (an allowance) for divorce. Confession, forgiveness, reconciliation, and restoration are always the first steps. Divorce should only be viewed as a last resort.
Are there any grounds for divorce beyond what the Bible explicitly says? Perhaps, but we do not presume upon the Word of God. It is very dangerous to go beyond what the Bible says (1 Corinthians 4:6). The most frequent additional grounds for divorce that people inquire about are spousal abuse (emotional or physical), child abuse (emotional, physical, or sexual), addiction to pornography, drug / alcohol use, crime / imprisonment, and mismanagement of finances (such as through a gambling addiction). None of these can be claimed to be explicit biblical grounds for a divorce.
That does not necessarily mean, though, that none of them are grounds for divorce which God would approve of. For example, we cannot imagine that it would be God’s desire for a wife to remain with a husband who physically abuses her and/or their children. In such an instance, the wife should definitely separate herself and the children from the abusive husband. However, even in such a situation, a time of separation with the goal of repentance and restoration should be the ideal, not necessarily immediately beginning divorce proceedings. Please understand, by saying that the above are not biblical grounds for divorce, we are definitely not saying that a man/woman whose spouse is engaging in such activities should remain in the situation. If there is any risk to self or children, separation is a good and appropriate step.