Generally, you can swap milk for cream in a pasta sauce. It will be a bit less full and not as creamy, but it's a good option if you don't have cream or don't want to use it. However, for a sauce with an acidic component - like the tomatoes in this recipe - milk may curdle if added to the sauce, which is why I recommend using heavy whipping cream. If you still want to try, use whole milk and first add some of the sauce to the milk, mix well, and then add this to the sauce while simmering over medium heat.