Congratulations on getting married!
I like that you are looking for the best of both worlds in Zanzibar - pearly white beaches, romantic resort and walking distance to popular bars/restaurants - but that is not going to be very easy to find!
First of all, if you want populated bars and restaurants, then you need to stay on the main island of Zanizbar (Unguja) because all the other islands are MUCH more quiet and probably too quiet for you.
Secondly, the busy bars and restaurants are generally in Stone Town because of toursim. Once you get away from Stone Town, the resorts become relatively quiet and there aren't a lot of busy bars and restaurants that you'll be able to walk to. Remember that Zanzibar's population is 99% muslim and they don't drink alcohol. Of course you can find plenty of bars at the resorts, but but don't expect to find lively bar scenes away from the resort areas in the smaller towns near the better resorts and beaches.
Unfortunately, the pearly white sand beaches are not found in Stone Town. To get that ideal beach scene, you need to get out of town and head to the North or East of the main island - but it's relatively quiet in those areas.
I suggest that based on your budget, you look at Echo Beach Hotel in Bewju. It's romantic, it's got very good food, a nice bar that can get lively (at least it was lively on the 2 times I stayed there), and it is also within walking distance of a few other resorts (both large and small and all on the beach, including Breezes Beach Club) which have bigger bars, some lively spots, and a variety of restaurants. And it has the gorgeous beach that you are looking for.
Finally, most of the hotels on Zanzibar are half-board. The more expensive resorts (Breezes, Serena, Baraza, Diamonds Dream of Zanzibar, etc.) offer AI and half-board. Serena is closer to Stone Town, by the way, and has the best beach in that area, so you'd have the option of going into town from there.
Hope this helps you! Happy honeymoon planning!