It might be
where the liveaboard is also. While most are focused on diving, Aquacat in the Bahamas also does some shore excursions.
Snorkeling Adventure Travel - Aqua Cat Cruises Also they have 12 single/double kayaks on board. The other nice thing about Aquacat is with all those decks your wife can get away from the dive talk when it becomes too much.
If there's space available, Cat Ppalu also does a range of excursions.
Bahamas Sailing Catamaran activities Although they market it as a full boat, there sell the extra spaces if available. Smaller boat so they only take 12 - four double cabins and two singles on the whole boat. Each has a vanity/sink but there's two shared heads/showers for the whole boat though. They would be one to talk to about a non-diver rate also since they're likely going to have a cabin free if a group doesn't take the whole boat.
The best by far for your wife will be Cuan Law though. They sail among the BVI's and are almost never out of range of some island. And always willing to take someone to it.
Things to do in the Virgin Islands: other activies on your Cuan Law cruise
Shore excursions are available almost anytime, with at least one shopping trip and hiking and other island excursions.
Even being a diver, I'd snorkel the Baths. The other thing about Cuan Law is that it's like sailing your house around - that boat has some room...we saw it once in the BVI's - it dwarfed all the 60-70' cats nearby. Cabins are the size of some normal bedrooms on land, they're ensuite and since you eat outside the main salon is always usable. They even offer massages on board. There's also two Hobie Cats for guests use. It is of course priced accordingly.
I don't think either offers a non-diver price because she's taking up a space and they're limited. Can't hurt to ask. Cuan Law also does sailing only trips so might be more open to that.
Spree might not be such a good idea because in addition to be a dive boat, it's all dormitory style with a couple of shared heads. Most of the bunks are in one area with curtains. No offense to Spree since I plan to be on it in the future but do you think your wife would like this:
JASA's boat - Shearwater has the same issue. So do the Blackbeards boats. Some of those even have some of the bunks off the kitchen - including the bigger ones for couples. If your wife doesn't like liveaboard living, she probably really won't like that.