you can get married outside and come here on visit visa and wait for the approval from the authorities. this could take 6 months to 3 years. if he knows someone in the MOI then it could be quicker. me and my husband got our approval to get married in 3 months. if they dont approve your marriage, i think he can still sponsor you but he will lose alot of his rights/benefits and your children will not hold qatari passports.

good luck