I feel my friend is manipulating me. anyone with a knowledge of psychology got any advice for me?

cut all ties with him or kick him in the balls, i say you do both. tell his friends and your friends and your family. power is in numbers and he is not strong. he is weak, a kid, he is not dangerous. he is the corruption in your life and to stop corruption you simply cut off its food, ignore him and don't talk to him and if you see him don't acknowledge him, he feeds off you and he knows it if he can't have you no one can, but you are the boss. stay strong friend and never let anyone change who you are.