I had the exact same problem as you. I loved someone for 4 years, and he never returned my feelings, and then I found out that he had a girlfriend. It crushed me to bits but then I realized that it isn't meant to be and I need to move on for my health. I cut off all contact with him and I don't see him anymore and it helps. I know that you will probably hear this all of the time but time does heal all wounds. Once you start living your life, and doing different things, without him in your life, then you will feel happier, and you will meet someone else. Trust me, it will be hard at first, I am going through the same thing are you are going through right now, and I am trying to keep busy to keep my mind off of it. Of course it will bother you, but you need to keep your distance from this guy and start looking at other guys. If you need to talk, please send me an email and we can chat. Good luck!