Zorro was the same. He would sulk when I would put him outside and stay at the door and whine. When I let him in he would just wait until I wasn't looking or when he couldn't hold it in anymore and go. Sometimes you could tell that he knew he was bad because there was a long trail of pee following him… hahaha
My boyfriend and I realized we had to go outside with him and walk him. Even though we wanted to be outside as much as he does!! He is so miserable outside that he goes pretty fast!!