Being able to support a minion^H^H^H^H^H^Hnon-working partner is a source of social status.
Is it worth working twice as hard?
At least, that used to be a widely-shared perception, back when this kind of thing was more common.
I guess it also depends on what your wife does in those n hours. (See also this, a couple clicks from Dalrock's post.)
Dalrock writes an interesting article related to Dr. Helen Smith's book the Marriage Strike. I really have to bump it up on my too rapidly growing reading list. (^_^)