A fault divorce may be granted when the required grounds are present and at least one spouse asks that the divorce be granted on the grounds of fault. Only some states allow fault divorces. (Find out whether your state allows fault divorces in Nolo's article collection Divorce in Your State.)

The traditional fault grounds are:

• cruelty (inflicting unnecessary emotional or physical pain) -- this is the most frequently used ground for divorce
• adultery
• desertion for a specified length of time
• confinement in prison for a set number of years, and
• physical inability to engage in sexual intercourse, if it was not disclosed before marriage.

Why choose a fault divorce? Some people don't want to wait out the period of separation required by their state's law for a no fault divorce. And, in some states, a spouse who proves the other's fault may receive a greater share of the marital property or more alimony.

What if both spouses are at fault? When both parties have shown grounds for divorce, the court will grant a divorce to the spouse who is least at fault under a doctrine called "comparative rectitude." Years ago, when both parties were at fault, neither was entitled to a divorce. The absurdity of this result gave rise to the concept of comparative rectitude.

One spouse cannot stop a no fault divorce. Objecting to the other spouse's request for divorce is itself an irreconcilable difference that would justify the divorce.

A spouse can prevent a fault divorce, however, by convincing the court that he or she is not at fault. In addition, several other defenses to a divorce may be possible:

• Condonation. Condonation is someone's approval of another's activities. For example, a wife who does not object to her husband's adultery may be said to condone it. If the wife sues her husband for divorce, claiming he has committed adultery, the husband may argue as a defense that she condoned his behavior.
• Connivance. Connivance is the setting up of a situation so that the other person commits a wrongdoing. For example, a wife who invites her husband's lover to the house and then leaves for the weekend may be said to have connived his adultery. If the wife sues her husband for divorce, claiming he has committed adultery, the husband may argue as a defense that she connived -- that is, set up -- his actions.
• Provocation. Provocation is the inciting of another to do a certain act. If a spouse suing for divorce claims that the other spouse abandoned her, her spouse might defend the suit on the ground that she provoked the abandonment.
• Collusion. If a couple lives in a state where no fault divorce requires that the couple separate for a long time and the couple doesn't want to wait, they might pretend that one of them was at fault in order to manufacture a ground for divorce. This is called collusion, because they are cooperating in order to mislead the judge. If one spouse decides he no longer wants a divorce (before the divorce is granted), he could raise the collusion as a defense.

But these defenses are rarely used -- for a couple of practical reasons. First, proving a defense may require witnesses and involve a lot of time and expense. Second, your efforts will likely come to nothing. Chances are good that a court will eventually grant the divorce, because there is a strong public policy against forcing people to stay married when they don't wish to be.

For the most complete set of books to help you end your marriage as quickly and inexpensively as possible, get Nolo's Divorce Bundle.

All states require a spouse to be a resident of the state -- often for at least six months and sometimes for as long as one year -- before filing for a divorce there. Someone who files for divorce must offer proof that he or she has resided there for the required length of time. Only three states -- Alaska, South Dakota, and Washington -- have no statutory requirement for resident status. In other words, being a resident at the time you file is enough.

If you think that your spouse may file for divorce in another state, it may be prudent to spend the money up front and file first -- in your home state. Rarely is a divorce settled in one court appearance, and, if your spouse files elsewhere, you could rack up a lot of traveling expenses. Also, any modifications to the divorce decree, including the property settlement agreement and arrangements for child custody and support, must be filed in the original state. This could keep you traveling out of state for years to come, especially if you have children with your spouse. (Get more tips on the divorce process in Nolo's How to Divorce topic.)

If one spouse meets the residency requirement of a state or country (such as having lived there from six months to a year), a divorce obtained there is valid, even if the other spouse lives somewhere else. The courts of all states will recognize the divorce.

However, decisions a court makes regarding property division, alimony, custody, and child support may not be valid unless the court had jurisdiction over the nonresident spouse. The court gets jurisdiction when the nonresident spouse is personally served with the divorce documents (meaning they are delivered into the person's hands), or consents to jurisdiction. A nonresident spouse consents to jurisdiction by showing up at a court date or signing an affidavit of service, acknowledging receipt of the filed legal documents. It can also happen if the nonresident spouse abides by the rulings of the court; for example, by paying court-ordered child support.

If you receive documents from a foreign country, you may want to consult an attorney about whether your state court or the foreign court governs the issues. This depends on many factors, such as which particular country is involved, where the parties lived and for how long, and, of course, whether children are involved.

For clear answers that can help make your divorce simpler and reduce your expenses, see Nolo's Essential Guide to Divorce, by Emily Doskow (Nolo).

"No fault" divorce describes any divorce where the spouse asking for a divorce does not have to prove that the other spouse did something wrong. All states allow no fault divorces.

To get a no fault divorce, one spouse must simply state a reason for the divorce that is recognized by the state. In most states, it's enough to declare that the couple cannot get along (this reason goes by such names as "incompatibility," "irreconcilable differences," or "irremediable breakdown of the marriage").

In some states, however, the couple must live apart for a period of months or years before they can obtain a no fault divorce.

How does your state handle no fault divorce? Check out Nolo's article collection Divorce in Your State to find out.