It was easy for me cause I had an American License,,, I didnt have to take any road tests or anything.. they just took and eye test for me and than I got a Qatari License, but I don't know if that's cause I was working for a big company at the time and they knew people or just because I was American and had an American License.. I am really not sure,, but like I said I am sure your not going to have any problems.
Trust me when you get here you must drive... it gets really hot here and you can't bare to wait on the side of the road for taxi.. not healthy..

Try to make sure that your fiancee trys to get a car allowance or a company car. Wish you Luck.. Look forward to meeting you!

Cheers Fairy