I used to be VERY jealous. I don't know if it has anything to do with your age, but I'm 29 now, and I was extremely jealous when I was younger. Not only do I think it gets better with age (well for me anyway) but I learned to really trust the man I was with (my ex now). He gave me nothing to be jealous about, always called when he said, and always wanted to spend time with me. When a man is all about you, you'll know it.
And then I think your jealousy will dissipate. And I now have that mentality like Stewie's Mom...if you (the man) want to leave...buh bye!! LOL