Hi Cathryn,
La Sagrada Familia is the most stunning building I have ever seen, get there early because it's packed with Japanese coachloads by lunchtime. The beach front is worth a stroll, particularly if your husband is partial to watching topless women, but the restaurants down there are a bit over priced for what they serve.
The city centre is full of quaint shops you can't get over here like Accesorize, Topshop. C&A, Next etc.
Where are you staying? The Aerobus is by far the best way to get into town from the airport.