A divorce, sometimes referred to as dissolution of marriage is the legal complete separation and division of a marriage. The process usually requires the authorization of a judge or some other legal permit based on different countries and their practices. Annulment is another term that may be used when referring to the breakup of a marriage, however there is a difference. An annulment is when a marriage is declared null and void by a person of law; as in, the marriage was never real to begin with or was never legal.
Dissolution of marriage is not permitted in some places around the world, however they usually allow an annulment to be done based on the circumstances. It is never usually simple and clear cut; especially if there is a child involved and if there are valuable assets.
There are quite a few other legal proceedings that may follow, there may be debate on who is best suited to keep the child (if any), and as such who gets to pay child support. With that also comes the issue of who gets to keep the car, house etc. There may also be a request for spousal support, more commonly known as alimony.
Previous to the 1970s in most states, a couple could not get dissolution of marriage unless there was "grounds" and they had to provide proof. The party seeking the divorce had to provide proof that the other party committed an act that broke a sacred vow; the most frequent cause was infidelity.
Since 1975 most states have adopted the "no-fault" policy, this is where a couple can get a dissolution of marriage, simply based on the fact that they do not want to be married to each other anymore. The commonly used reasons in these cases are incompatibility and irreconcilable differences.
The most practiced type of divorce today is the uncontested one; this is where both parties involved are able to agree on the separation process and the division of assets, usually without the aid of a lawyer or any type of counsel. Counsels are sometimes utilized, but the aim is for each party to come to a reasonable agreement and be able to present it to the court. In this case approval is generally assured. If the parties cannot agree however, they can opt for the court to make the decisions for them as to who gets the child / children and how the assets are split.
Collaborative dissolution is also becoming popular and is very similar to uncontested, however the parties usually need attorneys in order to come to an agreement and there is usually a negotiating process, where each party's attorney states why their client is the best person to keep whatever asset is in question, who is to keep the children among other things.