To dream that someone is leaving you means that you feel as being left out and unwanted. Perhaps you have hard feelings about someone not supporting you in the right way and leaving you on your own. The leaving could be interpreted only as the fear of being left. You are afraid that someone will leave you, because you do not know if you will meet his/hers expectations. If you are the one who is leaving someone, you are tired and wish for freedom.
Read more about dreaming of Leaving in other dream meanings interpretations.