Maybe Addison did n't have anything to do with it at all . " Ca n't get you alone , " he murmurs , and his breathing just keeps getting heavier and Derek can feel his hard - on against his thigh , not that he minds , but he does have a surgery in half an hour . And then he has dinner plans . With Meredith .
Question: Why should Derek not be alone with Addison ?
The answer to the above question:


Because he is cheating on the person is going out to eat with .