In a large skillet, add 1-2 tablespoons of oil, and saute shrimp and scallops for 3-5 minutes or until shrimp turn pink and scallops are opaque. Do not overcook! Remove and keep warm.
In the same skillet, add 1-2 tablespoons more of oil and saute shallots until tender. Add in the garlic; cook 1 minute longer.
Prepare the alfredo sauce:
Scraping the bottom of the pan, stir in broth and wine. Bring to a boil. Reduce the heat; simmer, uncovered, for 6-8 minutes, or until most of the liquid has evaporated.
Next, stir in cream. Cook, uncovered, over medium heat for 5 minutes or until thickened. Add the Parmesan cheese and stir well; turn the heat down to low and simmer until the sauce is thick. Salt and pepper to taste.
Cook the fettuccine according to package directions.
Drain the fettuccine; stir into the cream sauce.
Gently add in the shrimp and scallops; toss to coat.
Sprinkle each serving with tomato, parsley and, if desired, additional Parmesan cheese.