There will be others. However, you won't have to worry about stopping any of them. I'm going for an "Each girl gets one NTR guy for her." approach aside from Blake, who will be going for all of them. But, if you stopped him by cleaning his aphrodisiac from the vent, his NTR path is over. You won't have to do anything else to keep him away, he'll just be an insignificant side character. As for the other NTR options, it'll be like Roy (The dude with the blond hair.). You can go for a non NTR path where they don't exist at all. (For example, if you didn't check the crying sound, Roy wouldn't exist in the story at all.)