"... Nahida’s father had profited from the tradition of walwar, or bride price, which is a sum that prospective grooms must pay to the fathers of their intended brides. The money is supposed to be spent on household goods for the newlyweds, but is often taken by the girl’s family for their own needs.
In recent years, walwar has climbed to unprecedented levels, to the point where many young men can no longer afford to marry. The result, say observers, is that girls either remain single or are given to older, richer men instead."
Wealthy shieks can afford multiple wives while many young Muslim men can't afford one wife.