Your question is not a matter of immigration law but rather family/matrimonial law in the state where you reside. You may be able to use an alternative method of service if you cannot locate him. You may also simply be required to serve him at his last known residence. Speak to an experienced attorney in Oklahoma.
If you previously petitioned for him, you can withdraw the petition if still pending or notify USCIS of your suspicions of marriage fraud.
Answered on May 19th, 2016 at 2:39 PM