Definitely avoid Malta if you want warm and sunny in Feb! Well, it will have sunshine for sure, but the water temp ain't gonna be to everyone's liking!
Year round sunshine and warmer temps, I would suggest Lanzarote. Stay in Puerto del Carmen, dive with Safari. They are the only dive centre in the area with direct access to the sea (from their beach centre). 2 dives each day plus boat dives (at no extra cost) and night dives. Non-diving wife can sit on the beach and top up the tan while you get all salty. Plenty of bars and restaurants in the area, and not full of stag/hen parties either. The old town is full of tasty dining options. We've been 3 times and would recommend it.
Underwater there are wrecks, caves and swim throughs, plus plenty of marine life, from seahorses and nudis to massive eagle rays, grouper, barracuda, dolphins and the largest congregation of angel sharks on the planet. Feb is a good time to see them as well.
https://www.safaridiving.com/en/
https://turismolanzarote.com/en/