Part of Rob's route is available. In the scene where you need to choose between Hermes, Rob, or Drake, the Rob option should be visible to you. Is it for you? If it is not, you are not making the right choices.
Since you start the game until you return to your dorm and picture someone to have sex with you will be in the common route. After you reach it, Rob's option needs to be visible so that you can choose it.
