Even though there is a widening of gender roles, men are subconsciously expected to be the breadwinner. There is an unwritten expectation that men are to be the heads and breadwinners of their families. It is the old hunter mentality left over from cave man days. Men are supposed to assume the more dominant role regarding providing for their families.
It is assumed that if a woman works, she does it to fulfill her need for autonomy or for self-fulfillment. A woman is seldom expected to be the family breadwinner. If a man decides to stay home and be a househusband, he is looked down upon as not being fully masculine.
I remember 40 years ago, I discussed the concept of househusband with my mother. Of course, she was totally aghast. She informed me that man who depended upon women to bring home the money were p*****ps. Many people look in askance at men who desire to stay home and be househusbands. However, there are more acceptance of this role for men than it was 40 years ago.