You have to make a good faith effort to locate your spouse--internet, phone book, nearest relatives, etc. Once you have "exhausted" those options, you can ask the court to allow you to serve him by "publication." Generally, that means publishing in your local county newspaper and your local county legal publication. See Pa. Rule of Civil Procedure 1930.4 and 430.
Answered on Sep 16th, 2013 at 2:34 PM