OK so I've been given the brush off... but his behaviour makes no sense!?

Was he not aware that he had a dentist appointment until an hour before your date? I mean, call me crazy but I think you have to schedule those things. Chances are, his girlfriend was out of town and he had a week to have with you. Which is why he was trying so hard to get that first date, then she got back, now he's got to stop talking to you and erase all the evidence. These are just umptions though I could completely wrong.