My wife used to live there and her sister now lives there. That being said i have spent A LOT of time in SB. There are a ton of things to do in and around SB. Depending on how much free time you have and if you like to eat and drink there are some pretty good times to be had.
One of my favorites is to ride beachcruisers though what they call the funk zone. The funk zone is a bunch of breweries and wineries that are all pretty close to each other. Fig mtn brew is great, usually live music on the weekends. Santa Barbara Brew house is a good stop also.
if you feel like leaving SB(45mins away) there are a ton of pretty good wineries, nothing great like you would find up north but still good times.
Butterfly Beach, it sits in front of the biltmore hotel(four seasons) a small beach but nice. East and west beach can have a ton of seaweed on shore and can not be all that great to sit at sometimes.
there are a ton of really good resturants. Olio pizza/ or olio limon are both great(same owner). arc rock fish is good, they have a really good happy hour(early and late). The shellfish company out on the pier is also a good spot(stay away from longboards, which also on the pier). I could name 8-10 others depending on what you like.
If you get a chance you should try to do a quick drive through monticito, beautiful homes, and some really good restuarants as well.
Your wife will probably want to walk state street, just a bunch of botiques and what not. there are a couple decent bars on state street if she doesnt want/need you to go with her. stay away from sandbar and sharkeez, james joyce is a decent option that is somewhat in the middle of state street.
If you are more active, you could always rent paddle boards and take them to west beach. water is fairly calm depending on the day, good way to kill a couple of hours. Shoreline cafe in west beach is a nice spot to eat as well, the only spot in SB where you can eat on the sand.
I could go on and on, if you need any additional info or are looking for a certain activity i should be able to point you in the right direction.