Try locating the missing spouse
The first thing to consider is not to file a divorce without the missing spouse. There are many issues that cannot be decided if the other party is not present for the divorce. Issues such as splitting of retirement plans, dividing real estate, child support and alimony, cannot be decided without the other party being present. If there are complex issues such as the ones listed above, then you should make a good faith effort to locate the missing spouse and go through a traditional contested or uncontested divorce. Try to locate your spouse through former friends and employers, their family members or by searching in a telephone book or online. Only when you are convinced you cannot find your spouse, should you proceed to step 2.
What to file in court to proceed with a divorce
The type of divorce that you need to initiate would be a contested divorce even though the other spouse cannot be found and will not appear in court. A complaint for divorce along with all accompanying documents should be filed for a contested divorce. Speak with a clerk in your local family court to get all the documents. The Complaint for Divorce form should have a space asking you for the address of the other party. In that line you should write "Last known address: " and then list the last known address of your spouse. Once you file all the paperwork with the clerk and pay the court fee, you will ask the clerk to issue you a "Summons for Service by Publication".
What do I do with this Summons?
This summons is a legal document issued by the court commanding the other party to appear before the court. It is the instrument by which a lawsuit is initiated. The Summons will have the name of the newspaper where you will need to publish it for at least 3 consecutive weeks. Call the newspaper and tell them that you need to publish a court summons. Newspaper ads department will know what to do and direct you to send them a copy of the summons for them to publish. You will also need to send them a fee for publishing in their newspaper. You will also need to send a second copy of the Summons, via registered mail, to the address listed as your spouse's last known address. When the post office delivers the letter and cannot find the person to sign for the letter, they will send it back to you, unopened.
Now you simply have to wait until the newspaper has had time to publish the summons. Once they do, they will send you the newspaper clippings in the mail. You will also be receiving the letter you sent to your spouse's last known address back as a "return to sender." DO NOT OPEN THE LETTER! Take the unopened letter, the newspaper clippings, and the original summons back to the clerk. Fill out the back of the summons and file it all with the clerk.
You have now "served" your spouse by publication and the lawsuit can proceed. You can now proceed with getting a hearing date for the final hearing and everything else that goes with a contested divorce. Remember that this type of divorce will not allow you to get child support, alimony, any division of property or any other obligations imposed on the other spouse. If you later find your (ex) spouse, you can always return to court to open a case to adjudicate support and property issues.