Mushroom Shrimp Alfredo Pasta

Ingredients

• box dry fettuccine pasta
• butter, divided
• pint heavy whipping cream
• grated Romano cheese
• grated Parmesan cheese
• garlic, crushed, divided
• salt and ground black pepper to taste
• tablespoons olive oil
• large onion, chopped
• ounces diced mushrooms
• package frozen shrimp, deveined and tails removed, thawed