When I had surgery last December, I cooked several main dishes ahead, labeled them with the reheating instructions and put them in the freezer. That way, all my DH had to do is take it out of the freezer, pop it in the oven and microwave a vegetable to go with it.
Soup is always easy on the tummy after surgery. I'm one of those rare folks who wakes up from anesthesia hungry, but I still need to take it easy for a day or so because anesthesia can slow down your digestive tract and make it more likely that you will get an upset tummy if you push it. Go for light, easy foods like scrambled eggs or soup or sugar-free jello. Check the recipe section...there are quite a few recipes for very tasty soups (that would also freeze well) that would fit the bill nicely. Chicken broth with a bit of chicken or a raw egg stirred into the hot broth is always soothing.
Pain medications can also upset your stomach, so you may have to wait until afterwards to gauge what you feel that you can handle. In general, you might want to avoid dairy products for a few days (like cheese) because they can constipate and the anesthesia may already be having that effect.
Here's wishing you a quick recovery!