The family wants to see that any boy who is with a daughter is good to her and can be counted upon to support her. The cost of taking advantage of a girl can be severe. Anthropology contains ample instances of fathers or brothers who slay a false suitor who betrays a daughter or sister. Families are not so concerned about a son who has a casual romantic adventure. He is just sowing some wild oats.
Male genes can benefit from casual liaisons as well as from committed ones.
Nor is the family always so concerned about whether the girl is treating him like a prince or is screaming at him. It is better that a son be with some girl, even if she is mean to him, than with no girl at all. Any girl can transport the family genes into the next generation. So the inclination to protect our women from bad men provides a genetic advantage, whereas protecting our men from bad women would be genetic folly. By selecting those sensitivities which promote our genes, nature programs us to be outraged by men exploiting women but not by women exploiting men.