My girlfriend's best friend is a guy, I know him very well too. I don't know why but I sometimes get the feelings of jealously, he is closer to her parents than I am(long story, explanation is in Troubled Relationships section). I even sometimes get a small feeling he could steal her away from me. I know trust is key to a relationship and if I don't trust her 100% then it's not good.

Shouldn't I be the one who makes her jealous??