Additionally to family intrusions, you can see your (and maybe your parent's) bank account beginning to plummet as you plan your wedding ensuring success. Estimates put the average wedding in the $20,000 to $25,000 range and often a lot more!
Approximately 30% of couples end up paying for their own wedding this often means the difference between having a memorable one day event and having a down payment on a home. Thus coordinating everything... from photographer, to location, to dates, to relatives, becomes an increasingly painful experience.
Furthermore the average age of couples who decide to marry has slowly risen since the 1950's, consequently couples are more independent.
Often couples have lived together for several years, finally deciding they just want to legally consummate their relationship.