Well our parents were married, we had the advantage society gives respect to a family. Live-in relationship is a fancy name for free sex.
So-and-so is the son or daughter of so-and-so.. similary he is the father of our friend..the list of family generated help goes on... Once we become a part of a family, the society respects as a combined individual.
Live-in may be popular just for ads. Ultimately family wins....
