It's tricky. You're focusing on not focusing on your speech. I think the issue lies in the fact that there is a need to "focus". There is effort being put in in some form. Whenever there is added energy added to speak the system goes offline. Normal speakers sometimes focus on what they're saying, sometimes they don't, sometimes they themselves stutter, most of the time they don't. I think the solution is becoming indifferent about your stuttering. How? No clue.