I will go against the grain here rubecube......
Your girlfriends dad is not giving you the respect you deserve as a man. If it were me, I would stick to my guns and get the hotel room. You have to send a message here that you are not going to put up with this manipulative crap anymore. If he asks why you are not staying at his place, tell him exactly why. It will be good to get this off your chest and speak to the elephant in the room......maybe you and the ol' man will have a better understanding of eachother you know?
That is unless you like to live your life according to others standards in order to gain approval and avoid conflict........
