Just kidding.
Just tell him you're not interested. By talking to him you've led him on. If you flat out tell him and he still calls, then he is mentally unstable. I had a very similar situation some time ago....with the rolls reversed. Once I was told flat out, I stopped bothering her....which turned out to be the best decision of my life. But if I hadn't been told, I would have still pursued. Men are a retarded race who don't get hints...we have to be told "yes" or "no." So tell him "no."
