Your divorce won't be valid unless the court that grants it has what's called "jurisdiction" over you and your spouse. That's true for every divorce, but federal law provides that in order to make court orders relating to a military retirement plan enforceable, certain special jurisdictional requirements must be met. (If military retirement benefits are not an issue in your divorce, residency requirements may be more flexible, but you can't go wrong following the rules below.)
To ensure that the court you choose has jurisdiction over a military retirement plan, you must file for divorce in a state:
Remember that wherever you file, the laws of that state will govern your divorce -- not those of the state where you married or the state where your spouse lives, if those are different.
If you're a service member, domicile is defined as your permanent home, sometimes also called the "state of legal residence." You also have a "home of record," which is the state you lived in when you joined the military. This is an accounting term and doesn't affect domicile.
You can keep a domicile even while not living there, if it has been your home and you intend to return and live there permanently. Being registered to vote and paying state income tax in a state are two strong indications that you intend to return. Some other indications of your domicile include:
It's possible for spouses to have different domiciles. Be sure that you base your choice of where to file on the service member's residence or domicile.
Some states let service members file for divorce if they are stationed there, even if the service member doesn't intend to make it a permanent home. But there's a theoretical possibility that another state might refuse to recognize a divorce that's based on a rule like this, sometimes called a "faux residency" law. It's better to file where you are domiciled under the rules discussed above.
Most states require you to live in the state for a certain period (commonly, three to 12 months) before you can file for divorce there.
Some states require physical presence to establish residency, but most states consider military members who are absent from the state because of military service to remain legal residents during their absence.
The bottom line is, don't fudge on where you file -- especially if you're a civilian spouse. Retirement benefits are too important to risk losing because your case was filed in a location where the court doesn't actually have jurisdiction over both spouses.
If you and your spouse agree about where you want to bring your divorce action, you don't need to worry about jurisdiction. If you both participate in the divorce action without challenging jurisdiction, then the final judgment would probably stand up against a legal challenge later.
If you are stationed overseas or married to someone who is, you can still file in the United States. The proper place to file is the state where you are domiciled or meet the residency requirements, as described above. If you're a service member stationed overseas, you'll need an attorney in the U.S. to help you file at home.
Filing in the States from a distance is preferable to trying to get a foreign divorce, even though the foreign divorce might seem attractive if you're stationed where divorce is easy and inexpensive. But the military won't honor a pension division order from a foreign country, and it's hard to know for sure that your divorce judgment itself will be respected when you return to the States.