How do you know if its right to move away from a signficant other? Am I making a mistake by moving to nyc?

WE just met this past summer - we took things slow, real slow, just dated while seeing other people. I made my plans not based around him. NYC in Jan... but now we are close, we are exclusive and Im not sure I want to walk away from him. Deep down I think have to leave for my own life but I dont want to leave him.