I'm also a guy (who stutters) and my fiance is a person who stutters too. I've been on dates with other women prior to my current relationship..what I would usually do is advertise early on, something like, hey nice to finally meet you in person. By the way, I stutter, it's not cause I'm nervous, it's just how I speak..or something like that. But, I guess I'm curious, have you talked to him about that? If they already know, you don't need to advertise in person. As an alternative, if you haven't told them, you can also via text... But I think the fact that you've been communicating for a while means you two have a pretty good connection already. Also, I'm 100% sure your date will also have things they're a bit uncomfortable or insecure about, we all do. Lastly, good for you you're going on a date!