You might try cooking some spicy ethnic recipes, if agreeable to both of you - curries, Mexican dishes with chile, Italian recipes with lots of herbs and garlic, oriental things heavy on ginger. You will probably do OK just adding more herbs and spices to your favorite dishes - you may go wrong occassionally, but experimenting is the only way to learn what you like.
These "good pairings" might be a place to start
tomato-based dishes - basil, oregano, garlic, parsley, crushed red pepper
potatoes - rosemary, garlic, onions, thyme
beans - chile, oregano, garlic, onion
stuffings/breadcrumb type dishes - sage, onion, parsley, thyme
oriental dishes - sesame oil, soy sauce, ginger, garlic