Weddings are traditionally extremely stressful affairs. You wind up with a compromised affair, full of meaningless tradition, which costs more than your last 10 vacations combined.
Some couples meet and find romance through the bdsm community.
Several friends of mine have planned two wedding ceremonies. The first is a traditional ceremony, satisfying friends and family, and fulfilling any legal formalities in getting hitched. If you plan a bdsm wedding, you can let your fantasies take flight. If slavery is the basis of your relationship, you can stage an elaborate slave auction where friends can buy and sell their submissives for an hour or a day, but your sub is put up for a lifetime. Perhaps you have a more hedonistic streak.