I haven't been all over the world and so there are probably tons and tons of places that fit what you have described. But, my wife and I are both 57 years old. I dive and she doesnt. She has a drink now and then but I dont. So we have a little in common with you and your wife and of those places that we have been Blue Lagoon Beach Resort on Nacula Island in the Yasawa group in Fiji fits the bill to a T.
Probably not your cheapest choice if you look at air fare but once you get there things are very reasonable (thanks in large part to the current exchange rate). We liked the other resorts we visited in Fiji as well and had a great time on Kauai. But the atmosphere at Blue Lagoon Beach resort was tons of fun. The managers, Justin and Mel, are fantastic people that know how to do customer service. The food was great. They have something fun going on nearly every night in the restaurant/bar (it is an AI resort) and the vibe of the place was unlike any other we have ever experienced.
I was warned before going that I would probably be very disappointed in the diving in the Yasawa's but went anyway due to having had enough of the crappy weather we had in Bega for most of the four weeks we were there. The Yasawa's are in the drier part of Fiji and the islands there are what you think of when you think tropical island. The movie Blue Lagoon was filmed one island over...that will give you a good idea of what it looks like around there. I LOVED the diving at Blue Lagoon Beach resort. I MUCH preferred it to Bega. Kadavu is probably much better diving when the weather cooperates and you can get outside the reef but that wasnt the case when we were there. The diving at Naigani was much better in many ways but I loved the shark dive at Blue Lagoon.
So, again, from what you have said I think that you wouldnt be disappointed at all if you went to Blue Lagoon Beach Resort.
I am not now and never have been employed by Blue Lagoon or any other resort/dive op and have nothing to gain by suggesting Blue Lagoon.