I feel like you’re already passed the scary part. You’ve been seeing him and spending time with him. The fact that your stutter isn’t prevalent around him probably just means you’re pretty comfortable with him already, right? And honestly, he’s probably already figured it out if you’ve blocked or anything around him. He won’t care, and most likely already doesn’t care, and if he did then he’s not someone you want to be with because what you’ve already seen of him that you like unfortunately isn’t his completely true self.