I am looking for vacation suggestions for a romantic destination for my husband and I that includes snorkeling. I would like to go somewhere that does not have spring breakers (alot of high school/college kids) since we are going during March. I would also like to go somewhere that has a lot of culture. Budget of less than 4000.00 for airfare/hotel. Thanks for any suggestions.

Hawaii has some bargains now..

don't know where you're flying from but if you want to snorkel in march i would suggest you fly to st. thomas usvi. then either stay on st. thomas or take the ferry (45 mins) to st. john.
st. t is busy, st. j is much more laid back.
st. john will have less spring breakers as it is quiet.
grand cayman would be an excellent alternative for snorkeling.

Don't know about the spring breakers, but Bermuda has some great snorkeling. Lots of history, and the US Dollar is accepeted everywhere, the exchange rate is
1 USD = 1BD

Although I didn't snorkel when I was there, I understand that Belize has world-class snorkeling, at Ambergris Caye. You can tour fascinating Mayan ruins nearby, and bird-watch (toucans, three kinds), and see howler monkeys, and take a zipwire through the jungle. Belize is famous for waterfalls as well.