If he has never entered the U.S. without inspection, and he is currently in Mexico, then you would need to apply for either a K1 Visa (fiance visa) or a K3 Visa after you are married. If you can prove that you two are in a real relationship and have met each other in person, then you should have no problems applying for a K1 visa. You should seek the assistance of an immigration lawyer to help you with your petition.
Answered on Feb 13th, 2017 at 8:53 PM