Congratulations on your upcoming wedding and honeymoon cruise.
Cruise prices these days can look very low, and in fact, many are low. The price doesn't include a host of taxes, fees and surcharges the cruise lines add on. When you see a really low price, it's usually the per person, per day price, without taxes and fees added in.
Those prices, like the one you booked, are available from every travel agent, and not just whatever site you booked from. Sometimes, travel agents have lower prices than what you find on a web site.