How to stop being so paranoid with relationships?

[Max]

My girlfriend and I are a good couple so far. It's just we have gotten into a couple fights because of my paranoia. I have a tendency to get scared of other guys taking her away and never feel comfortable. I don't know what to do to get rid of this paranoia... It's really bad too, as in I constantly am checking her facebook and IM status' to see of anything... Help? And be rational too please, not just like "stop caring and it's all good" That won't work, please and thanks!