You can ask the court by motion to allow you to serve your spouse by alternative service. You attach an affidavit that a defendant has acted to evade service and list the attempts made to effect service.
The court may then order that service be made by (a) mailing a copy of the summons, complaint, and all other papers filed with it to the defendant at the defendant’s last known residence and (b) delivering a copy of each to a person of suitable age and discretion at the place of business of the defendant.
If you the above method of service would be inapplicable or impracticable, then the court may order any other means of service that it deems appropriate in the circumstances and reasonably calculated to give actual notice.
Maryland Rule 2-121