In a slow cooker, combine the sausage, onion, garlic, tomatoes, wine, tomato paste mixture, thyme, oregano, bay leaf, salt and pepper. 

Cover, and cook on low until the tomatoes are broken down and thickened, about 7 hours. 

If the sauce is too thick, add water 1/4 cup at a time until it has thinned.

Bring a large pot of salted water to a boil over high heat. 

Add the spaghetti and cook until tender, about 8 minutes. 

Drain.

Meanwhile, use a large spoon to skim any oil from the top of the sauce and discard. 

Remove sausage from the slow cooker and cut into thirds. 

Ladle the sauce over the cooked pasta in a large bowl. 

Arrange sausage pieces on top and sprinkle with cheese before serving.