Although its by no means official, i know plently of people in Dubai and Muscat who "were married" so to speak. Many people put the ring on the finger but dont have the paperwork.
In some areas it is best to say you are married and make sure she has the ring on as even living together unmarried is a big no no. Basically say from the beggining to evreyone you get to know that you are married
She will get loads of unwanted attention especially from sleezy taxi drivers if she doesnt have that magic ring on. Come to think of it she will get unwanted attention full stop from the taxi drivers!
Hope this helps