I will have to say, my wife and I do the same. I take a guys' trip--to Vegas, or golf; she takes a girls' trip. Usually hers is to a beach.
Not saying we are the perfect marriage by any means, nor am I saying those trips are responsible for the success we do have. but we recognize each other's space.
You bring up an interesting phenomena. It seems that modern marriages are all about the "best friends" concept between husband and wife. I'm not sure we took that approach--we have a marriage together, not a friendship.
My Gf and I were best friends for quite a while before we became romantically attached. Lived next door to each other and drove to the gym (both gym rats)every day and came home and cooked(another shared interest) and shared meals at night. Have a couple of other interest that bring us together. Works for us.