Why does he act like a bigger perv?

I think if you just started dating someone you probably don't need to be running off to a hot tub room with them, but he looked at other girls because he's likely a curious and horny teenage guy.

Do you want a guy you just started dating to take you to hotels where you have a good idea what he's going to want to happen or do you want a guy that's going to bring you flowers and walk with you holding your hand (they exist!)? Your call.

Not quite sure I understand but. You two just talked about going to a hotel/hot tub. But you weren't there. Then you go to the girls bathroom (like at school? ) and he looks in the door?

Well, that's kind of rude and embarrassing. But if it was a one shot deal, well I wouldn't read too much into it (and I don't see what it has to do with the hotel). But if he's showing a pattern of being a peeping tom, he's got a problem so move on. If he just checks out girls aggressively/rudely, he's got a lesser problem but tell him its rude and you won't put up with it. If he cares, he'll at least try to stop. If he doesn't care, move on.