As worldbuilders, we need to bear in mind that the way that seems right and natural to us today is the current point in a long and continuing evolution, and not the way things have always been among all right-thinking people. 

Which isn’t to say that I don’t think the way my marriage works is great: legal equality, mutual respect and affection, freely chosen by the partners. It’s just not how marriage tended to work historically. Even my wife’s grandparents married, as far as we can tell, largely for pragmatic reasons.

http://www.collectorsweekly.com/articles/how-romance-wrecked-traditional-marriage/