The Five Year Itch

This website (TopNews.in) says that scientists in the U.S., Russia and Scandinavia have determined that the honeymoon period in relationships lasts less than five years. They say that if a married couple makes it to their fifth wedding anniversary then they're much more likely to make it over the long haul. Though this article doesn't offer references, it does give reasoning to this timeframe. They say it's because couples are typically going through life changes in the first five years of marriage, such as finishing education, bearing children or establishing a career. It also makes sense, then, that the article says couples who marry later also have a better survival rate.