It is the whole concept of traditional marriage. The man and woman leave their other families and join together as one unit--each their own personality and individual self--but one marriage that does what it needs to in order to get things done. You work it out. And, in my opinion, because the way most men and women are naturally wired, it just works out better for him to be head of household and chief bread winner and for her to be the heart of the home and the glue that holds it all together. When it works as it should, both can be the best they can be, will have chosen their way of life, and will be happy.