Congrats on the wedding plans!!
Just wanted to give you the low down of the island night life. Like it was said before if you ask, anyone they will tell you where the party is. But there are nights that there are regular "parties" going on. Nevis is a quit island so the word party is kinda a big word.
Monday nights- Chevey's on the beach- kareoke and a great place for a drink and socialize
Tue nights- Oualie Beach Resort- Beach BBQ and live music, Lots of people and a great time
Wed nights- Eddies in town- No more Kareoke, but great dancing and a lot of fun, good food too.
Thur night- Nesbit Beach BBQ- The best band on the island playing plus a great seafood buffet
Friday night- Oualie for live music, (sometimes quiet) or V's Court yard in town for dancing. V's is a hot spot and night club like.
Sat. Night in town- Sometimes court yard or Night moves by the pier is nice.
Sun night- Sunshines on the beach.
There are a ton of things to do. There are many great restaurants if you like to dine and there are nice lounges, like coconut grove or even four seasons to just hang out and enjoy each other.
The Botanical Gardens also does Tapas at Sunset and has a great view.
I don't think you will have a hard time finding things to do here in Nevis, just ask around, it is a very friendly island and the locals will always point you in the right direction.