What does it mean if you had a dream my girlfriend cheated?

Normally dreams can play tricks on our mind, to make us paranoid or even take things to extreme levels. its probably nothing to worry about, its just what you dread most, and its bound to pop up in your mind. It happens all the time, like some people have worst case senariOS in their dreams, such as death. And this would probably be your worst case senario. Its just paranoia carrying on in your sleep.