You have to be married first because in order to petition for him, he must have a US citizen spouse. However, he will need a waiver of the 10 year bar to reentry, and that will only be granted if he can prove extreme hardship to a US citizen spouse. This is fairly difficult to do in most cases. You should really consult with an immigration attorney to understand what your chances in this would be, given your specific set of circumstances.
Answered on Mar 27th, 2012 at 1:40 PM