This is the most common, completely natural form of jealousy: the little twinge you get when you see him drooling over Angelina or paying your best friend a compliment.
For a couple of seconds you might lose your self-confidence, but then your ego kicks in and you force yourself to make a bit of extra effort to show him YOU are the the most beautiful, sexy and intelligent woman that ever walked the earth.
Don't forget that someone who's feeling a bit neglected will often play around and flirt a little, harmlessly, to make their other half jealous and get his or her attention back. It's fine...in moderation!