If you already told him you have a stutter and he’s ok with it I wouldn’t worry. Just be yourself and stutter in front of him. Better to get it out the way and see if he was honest when it said it didn’t bother him. Your killing 2 birds with one stone. Seeing if he’s ok with it, and also being comfortable around him. When you stutter intro things and get relaxed you probably won’t stutter in front him anymore. Life is short, have fun!