Cook spaghetti according to package instructions until al dente. Drain and set aside.
In a large skillet, cook bacon over medium heat until crispy. Remove bacon and set aside, leaving the fat in the skillet.
Increase heat to medium-high. Add scallops to the skillet in a single layer, season with salt and pepper, and sear for 1-2 minutes on each side until golden brown and cooked through. Remove scallops and set aside.
In the same skillet, add olive oil and garlic. Sauté for 1 minute until fragrant.
Add heavy cream and bring to a simmer. Reduce heat to low and stir in Parmesan cheese until melted and smooth.
Return spaghetti, scallops, and bacon to the skillet. Toss until everything is well coated in the garlic cream sauce. Season with salt and pepper to taste.
Stir in parsley and lemon juice. Serve immediately.