Anecdotally, my husband (fiancé at the time) and I were denied check-in at a hotel in Qatar unless we got separate rooms. When I had researched before reserving, I recalled that a marriage certificate was required for Qatari national citizens but found expats wouldn’t need to be married. As it turned out, since my husband held a Tunisian passport, meaning he was from a Muslim country, they required a marriage certificate for us to stay together.