In the dating world, there are certain things you just don't do. Okay, to be fair, we all do them—but we wish there had been someone there to tell us not to! In this excerpt from Sex with Your Ex, Dr. Fulbright clearly lays out the seven biggest dating sins for all the world to see (and avoid). So next time that little voice in your head tells you to pull a When Harry Met Sally in bed tonight or check your ex's away message, you'll know better!

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