Having observed many more divorces than I am happy about, there are multiple causes for it, and it is rare that two cases are the same. There are many factors that enter into the equation. Some are grounds for therapy, modification, and change. This includes either or both of the individuals (referring to needed individual work) as well as re-education on how to handle marriage (communication, learning to respect and cherish each other, etc.)
There are other matters that are not so simple. Here are just a few examples.
Family interference. One cannot blame a young recently married man or woman from sharing their issues with their parents or other family. However, this is often a tragic step. The tendency is that family takes such information as a battle cry, rather than a cry for help. Instead of helping the couple reconcile differences, they often take oppositional stances, and introduce a level of conflict that may not have been in the picture before. This triggers a counter response, and we now have a war where the issues might have been reconciled. Once at war, it is a very steep climb to convert the situation to something manageable.
Either of the couple may have some latent issues that were not known before the marriage. More often than not, this is a condition that was not disclosed during the shidduch phase. I have known of this involving medical conditions and psychiatric disorders that were simply kept secret. On occasion there was rabbinical support for this, which is hard to fathom. I do not take to a hechsher on dishonesty very well.
There are more ways than cheating than the most commonly understood one. While I am not the one to blame technology for everything, it does become a tool that makes communication easier, and it also has addictive qualities. These can push the spouse away from his/her priority status, and this can become such a wedge that restoring a marriage is almost impossible.
Dishonesty and secret keeping are horrible ingredients to a marriage. If one cannot trust their spouse, there is no basis left to feel safe, loved, or valued.
Support systems can be lifesaving for many people. But they can also be toxic. When a couple hopes to restore a loving relationship, but either has a group of peers who are convincing them to do divisive things that undermine the repair of a relationship, the match of forces may be a recipe for disaster. Therapists often complain that their best efforts are thwarted by these support systems.
Bottom line – no one gets divorced for fun. It is not recreation, and it provides pleasure for no one (except the therapists, toanim, lawyers, and dayanim who can milk the two parties for their personal gain). The decision to end a marriage is because it is assessed to be the lesser of the two evils. Perhaps it is true that some reach that decision in haste. But the wrong helpers contribute much to the overall problem.
It is also its own dialogue – are our chassanim and kallahs properly prepared for marriage? If someone wishes to open a new thread on this, it might elicit some useful ideas. I would say that the best efforts of those engaged in teaching chassanim and kallahs are still wholly inadequate.