I think alot of people marry too soon after meeting. They don't have a clue what each others' quirks or habits are. And I NOW am a firm believer in living together before marriage. Of course when I was young and before I married the first time (stupid and married at 18) I didn't believe in that as I was brought up Catholic -- and heaven forbid that you had sex before marriage!

But now I think you should take some time to figure out if you can STAND living together as some people are total SLOBS.
Plus some people DO change after you live together/get married. They get a sense of "ownership" over the other and start to become controlling and/or abusive. It's best to find out before the marriage license. That happened to me, and after my divorce my 2nd husband and I lived together for about 4 years before we got married. AFter we both had failed LONG-TERM marriages, we wanted to be sure.
And I think alot of folks don't "re-invent" the marriage because they just don't have the incentive. They're just so bored with the marriage, they just go with the status-quo.
Just my thoughts and experience. Take care. Lee