CocoView Resort, Roatan is EXACTLY what you are looking for!
I think the place is very romantic, too. It is rustic little cabins over the water, no tv, no kids... aaaahhh. Relaxing! Shore diving is easy, walk right into the water, walk right out. And as far as the boat dives go... they have boats that are easy on and off (sit low to water), plus a moon well to climb up if the seas are a little rough.
Walls, wrecks, all you are looking for!!
CoCo View Resort Roatan Scuba Roatan Diving located in Roatan, Honduras diving, scuba and snorkeling.
It is not the cheapest place on the island, but that is for a reason! The staff are amazing, the food great, the boats great, the personal service makes you feel special, and then the fact it is very small and only divers... you cannot beat it anywhere in Caribbean. There is a shark dive that people can book through the resort (not included in CCV price) but I have not done it. I have heard good and bad reviews about it. There is also a dolphin dive (at another resort) that some people do that gets good reviews.
I have also heard people enjoy Anthony's Key Resort on the other side of Roatan. It is also considered romantic but it has more families (with kids) and a bit larger overall. I have also heard that their shore diving sucks... but that was from a friend who did CCV several times so her viewpoint may be slanted. She also said that the staff at CCV was much better than Anthony's.
If this looks like what you want.... book as soon as you can. The resort fills up months in advance!!
other places you mentioned:
Bonaire is good diving, but I don't call it romantic or an anniversary special-type trip. It is too much work dragging tanks in and out of your truck for all the shore diving, IMHO, to call it a relaxing trip.
Bahamas I have only done by Liveaboard and those 2 trips were some of the best dive trips we have ever taken. We just love liveaboards, plus they get you out away from the crowds to the best diving areas. I have heard that the best place to go land-based in Bahamas is on one of the outer islands, but we haven't done that so no personal experience.
St Croix.. haven't been, but I have seen some nice photos and heard it is romantic.
robin