Bring a large pot of salted water to a boil, add the rigatoni and cook for 1 minute less than the package directions; reserve about 1 cup of pasta water then drain the pasta.
Heat a large sauté pan over medium heat, add the olive oil and sauté the chopped garlic until golden and fragrant, about 1 minute.
Stir in the diced tomatoes, heavy cream and whole milk, then simmer gently for 2–3 minutes while stirring.
Add the peeled shrimp, peas, salt and pepper; stir to combine and cook until the shrimp are opaque and cooked through, about 8–10 minutes.
Add the drained rigatoni to the sauce, toss to coat and cook 1–2 minutes more, adding a splash of reserved pasta water if needed to loosen the sauce.
Serve immediately.
Notes
Avoid sautéing the shrimp for too long, as they will continue to cook in the sauce.