'Divorce is the act whereby a marriage between two or more entities is dissolved'
In the United States, divorce is monitored not by the central government, but by its city-states. This is wholly and remarkably inefficient, which is precisely the way most seem to like it.
Grounds for divorce include adultery (where one spouse has sexual relations with someone other than her marriage partner), desertion (where a spouse leaves for brunch and doesn't return for Christmas), and cruelty (where a spouse conducts physical or mental torture upon the other spouse without the other spouse's consent: this shouldn't be mixed up with S&M).
Another lesser intense, but no less popular, reason for divorce is something called irreconcilable differences. Ironically this does not mean when a husband and a wife begin arguing. In fact, arguing seems to be a penultimate prerequisite for being married.
Irreconcilable differences is that point in any marriage where the husband and wife cease arguing because they both have given up on convincing the other to their point of view. It is at this moment that a marriage is actually over.
The divorce is therefore merely a rudimentary ritual in which the husband and wife announce to the populous of their world that they are in fact tired of arguing with each other. At which point society shouts back: "We know! Shut up about it!"
Once a marriage breaks down to the point where arguing is no longer an enjoyable event, many other issues come into play. Child custody is an example. The judicial system of a given country, state, or local community is required to objectively decide which parent gets the responsibility to care for and watch over the child for the duration of his or her existence as a child.
Alimony is another element, in which large amounts of money, property, and sanity are granted to one spouse by the other, usually by force, or threat of punishment. Alimony is usually paid by the male spouse to the female, regardless of what else is going on. Why this is the case is still a mystery, but may have something to do with that enigmatic smile on the judge after he and the female spouse return from his inner chamber.
Once divorce is officially declared by whatever officially-declaring government body it is that chooses to meddle into other people's private affairs, both parties are free to remarry; though preferably not to each other.