I've also heard that the first one to two years of marriage are rough. Many expect it to be just great and awesome, but I personally know several couples that have had just really difficult times.
It's not necessarily a bad thing though. I think working through the difficulties that a couple faces will give an even stronger foundation for their relationship. I think many couples that get divorced within the first 5 years delude themselves into thinking that the rough patches don't exist, and they have no problems that first year. Consequently, the things that need to get worked through never do, which tends to lead to disaster.
Granted, some couples really do seem to have it easy, but from the people who I know who are ridiculously happy in their marriages, this seems to be the general story I get.