I would go as far as to say that D/s relationships can and are, often vanilla. My brother and his wife have been married for over 35 years now. Their relationship is as close to a TPE as you can get without all the leather, whips, and cages.
And if you happen to stumble on the Taken in Hand site, you realize that this is a group that is structured around the goal of real life D/s without the kink. This group believes that spankings are a vital part of maintaining that balance.
I see D/s relationships in staunchly religious households as well. A few weeks ago my husband had to stop me from gawking at a large family sitting at the next table. This was a family-style restaurant where the meat and vegetables are shared. The man at the head of the table was so obviously dominating over the wife and children, he stood up and served each one of them what he thought they should eat. Then led them in prayer (rather loudly) before sitting and taking the first bite which signaled that they were allowed to eat.
(God bless Texas and the big blingy bible belt it dons.)
Anyway, you get my point. D/s isn't just part of BDSM.
