What about Northern Tenerife - Puerto de la Cruz?? Plenty to see and do. The north of the island is a lot greener and prettier than the south (Playa de las Americas & Los Cristianos) Also, Funchal in Madiera is lovely. There aren't any sand beaches as such, but plenty of relaxing spaces, history, culture, the most amazing scenary and gardens + madiera wine as well.
Thirdly, I would comsider Lucca in Tuscany. The most beautiful walled city, within easy travelling distance of Florence. Monecatini Therme is close by with lots of spas etc. for relaxing.
Ann x