Cook pasta according to directions. My general rule of thumb when cooking pasta is about 16 cups of water with a generous pinch of kosher salt. Bring water to a boil and add pasta, cook for 10 minutes. Drain well.
While the pasta cooks.... add 2 tablespoons of butter to a large skillet. Heat over medium heat until butter is melted.
Add the celery and onions to the skillet, I used a Vidalia onion because they're in season, and cook until translucent. This will take about 5 minutes.
Add the lobster, crab, and shrimp to the skillet and saute until heated through then remove skillet from heat and set aside.
In a large mixing bowl, add mayonnaise (I use Dukes) , lemon juice, Old Bay, salt, pepper, and parsley. Whisk to combine.
Add the sautéed seafood and veggies to the mixing bowl and give a stir to combine.
Finally, add the cooked pasta. Stir to mix it all together.
While this can be served warm, my preference is to chill it in the refrigerator for at least half an hour, then serve.