Hypergamy

Hypergamy is the practice of dating or marrying someone of a higher social status than oneself. Hypergamy is usually associated with women. Some sociologists believe that harems formerly existed because of female hypergamy. Some analysts also believe that people have twice as many female ancestors as male ancestors because of female hypergamy.
For the better part of human history, women simply didn’t have the option, access, or legal rights in many places in the world to have agency over their own welfare and to create financial independence. So, they relied on a 'good marriage' to secure their (and their children’s) overall prosperity and prospects.
While many Western societies have progressed to promote gender equality in the past century—attempting to creating equal career, educational, and financial opportunities for women—there's still a large gender pay gap. For example, in the United States, women are paid roughly 82 cents for every dollar a man makes for the same job, and the disparity is even greater for women of color, according to the American Association of University Women.