Yes, the keys can be a parking lot of dive boats.
My latest trip, I went down for Veterans day. Rainbow Reef offered free diving for vets and they have their usual package deal of dive + accommodation .
First day was great, not much traffic, but not my preferred site [Benwood or French reef}.
Second day was horrid. A group of scuba-holes held up the AM trip by not being prepared which changed our destination from the Benwood to a reef. Second dive was on the same reef, with a 5 min SI.
Keep in mind these boats are on a schedule and need to be back for the PM trip, so if someone slows things down, well.....
Oh, and one of them brought bananas, wtf? You'll get perma-banned in my AO for such an oversight.
I have been planning a trip with Conch Republic, but the problem is a place to stay....Keys are not cheap.
CR will go to places that the heard will not. I have dove with Capt Slate as well, which will take you to sites that are less travelled.
My fajita maker is like your SO, she just wants the beach etc read a book etc.
No beach to speak of in the keys. Unless you stay a place that is on the beach = $$$
Points North of the Keys, big hell ya [my AO].
Anywhere from Jupiter on down to Ft. Lauderdale has awesome boat diving. Wrecks, reefs, big critters [sharks, turtles, rays, jewfish]
Staring in Jupiter, Jupiter Dive Center. West Palm Beach, Narcosis Dive Charters. Pompano Bch, South Florida Dive HQ. And there is plenty of shore diving in Broward Cty.
Weather is iffy though, this time of year. Eg, this week conditions were fine midweek, but not so much afterwards.
Narcosis runs a 48' boat, so they are known for going out when others are sipping cocoa. Very professional and experienced boat.
Best of all, there are plenty of beautiful beaches for your SO.
We are looking at trip to Coz this summer, but if that doesn't pan out, we will be going to Keys
LMK if you have any questions.