There are exceptions to this though, take my parents for example. They've been married for 35 years and still act like newly weds. Plus there isn't a day in all of my childhood where I can remember them arguing or even raising their voice to one another.
Perhaps my childhood has led way to a slightly jaded perception on marriage since the majority of them seem to fail, but I would like to think that I could have what they do....at least during some point in my life.