I am a DW and I drive about half the time. When we decided to start RVing, it was a given that I would drive because I don't like to be helpless and as we all know, stuff happens. If I wasn't going to drive, we weren't going to start RVing...period...my decision.
Actually, when we go on long trips and when we start full timing, the agreement is that I do most of the long haul towing on the freeway, and DH will do most of the city driving. I can put in the hours on the road pretty easily and he gets drowsy. I hate driving the rig in the city.
IMHO every adult on the trip who is capable of driving a vehicle should be familiar with driving the rig. But that's just me.