First of all, you're not pretentious and you're certainly not idiotic. How were you to know that he would be like this in person? You had no warning in all your conversations did you? Please don't blame yourself as we can't control other's actions.

Whatever reason he had why he behaved this way, be it nerves (then avoiding you out of embarrassment), changing his mind or just being a strange man, they don't really matter in the end. He's treated you badly, and although it's hard when a person doesn't explain their actions I think that the best thing is to put him out of your mind - you deserve better than someone who plays games. Much better. Hold your head up high!

I hope you won't blame yourself, and try to move on - please be kind to yourself.

Hugs.

By the way, as a gemini, I won't hold your comments against you! And nah, I think its nothing to do with star sign, he's just behaved badly.