His job is to intimidate you so that you don't screw up and realize that your girlfriend is someone that should be important to you and not some one night lay.

Your job is to understand his job and agree that your girlfriend is not some one night lay and she is important to you. If you take this attitude then soon enough you will both see eye to eye. Don't push it, it’s a trust thing and the fact that he is not rushing to buddy buddy with you is a good thing in my opinion. Nice to see a real father these days.