I don't agree with the 90-day dating rule and I think it's not for every dating situation. There are men out there who are just as much a good catch as good women and sometimes you could lose a good man all because you want to play the 90-day dating rule game.
Just because he doesn't want to wait 3 months for you does not make him a horrible person or a shallow one either. I'm not saying you should give it up without knowing the person from a personality perspective, but you can't apply this method to every dating situation.