If you really love someone you never fall out of love, if you do then you probably shouldn't have been with that person in the first place. I don't settle for second best in anything I do and I damn well won't do that for love. Most divorces are because people didn't get what they wanted in the first place. My parents married in 1968 went their seperate ways in 1994 but never got a divorce and since last year have tried to reconcile their difference. Did they find anyone else between then, no because they knew what true love was and realized that whatever differences they had weren't worth giving up 26 years of marriage over. Most people now a days meet, get married and then divorce all in a year. Its the wham, bam thank you ma'am philosophy. I believe in courtship and knowing someone before I do anything.
An edit... most people get married these days when they are 21-25. My mom met my dad when she was 18, they dated till my mom turned 26. They dated for 8 years, thats a good enough time to get to know a person.