Let's say the logic of this world, men always looking into young women under 20, when their wife get old over 30, they considered as grandma and living separate room, they have a choice to devour as long as their husbands accept.
With this condition the MC who has weird taste of women compared to rest of the men in this world, can make his MILK harem without any problem as long as he followed the rules and get accepted by their husbands, specially if he is a hero which allow him to have many wife.
I enjoy the mother fucker!!