What types of things interest you and your husband? museums, outdoors, beaches, country, city, etc?
Would you want to city hop or just pick one or 2 cities to explore?
Are you guys american? how’s your spanish?
In Barcelona the Picasso museum is a MUST! And make a trip to the St. Josep La Boqueria (that is where you will see REAL spain)
I would suggest going to Segovia if you are in Madrid. It is about an hour outside of madrid and can be like a day or ½ day trip. the town is small so it won’t take long to look around.
i really liked the reina sofia (modern art museum madrid).
if you are there during a soccer game you might consider getting tickets, but they get really crazy, so be prepared.
i haven’t been to seville but i hear its a party city (but then again pretty much everywhere in spain is a party city).
my biggest “hint” to you for your trip is keep your eyes, and hands on your purse/ wallet/ money at all times. pick pocets are pretty slick there.