Just to make sure the situation is clear:
There are two couples who are neighbors.
The woman in one couple is named Davis, and the man in the other couple is named Davis.
They are not related by blood or marriage.
They are the two indecisive ones regarding the rugs, etc.
Their spouses in this particular situation are peripheral, certainly without strong opinions about the rugs.
(Though it is not clear why.)
The male Davis’s wife appears only in the scene in the driveway, not at the post office.
The female Davis’s husband appears only once, when his opinion of the rug is mentioned.