Marriage has existed in some form or other since the dawn of civilization. Originally it was a very mixed insitution, with all sorts of permutations; some societies allowed many wives, while others allowed many husbands. Some prohibited certain unions (e.g., a widow with her husband's brother), while others required the exact same match as a matter of course. Some expected that the wife should submit to the husband and give up her name for him, while others found that idea pretty darn silly. Marriage changes with every generation, and that's one huge reason that it has lasted. It keeps what is essential about itself and sheds the baggage of patriarchy or other out-of-date ways of thinking.
A common myth is that marriage is in decline, but actually the Millennial generation are far more likely to value it. Partly this is a product of the fight for marriage equality, that required a generation of young people to think deeply about why marriage matters and conclude that they wanted it for themselves and others. Partly it's a product of seeing the Boomer generation - who had more divorces than both their parents AND their children - throw a lot of the proverbial babies out with the bathwater. Partly it's because nobody can afford not to live with another person anymore! Millennials are thus more pro-marriage, delaying it longer and being far more likely than their parents to stay married. They're also MORE likely to stick in their marriages when the woman earns her own money, the opposite of the previous generation. Thus, we can see, marriage changes as society changes, but it never goes entirely out of fashion.
How do you feel about marriage? Let us know, and we'll figure out which generation you're from!