It sucks but there is no magic cure for stuttering. The only thing that has helped for me was lots and lots of practice. Literally doing my own exposure therapy. I had a hell of a time in college, and considered quitting in the middle of med school, but at this point in my life I have started to give way less fucks. I'm a psychiatrist now, and I spend most of my day talking to people. If business is your dream, please don't give up on it just because of your stutter.