I’m not sure why people are reacting to your post so strangely. The dopamine created by watching porn can be used to cope with many things, including stuttering if it is causing to become stressed out. And of course it is very addictive. So while it is not causing your stutter, the stress it causes for you may be driving you to consume more porn. I’d recommend you do your best to quit, because it is so addictive and unnatural imo.