I see you asking about will it reduce over time etc. Obviously, every stutter /stutterer is different, but I have a stutter similar to what you're describing. I tell people I am not a first impression kind of guy, more like 3rd or 4th impression. I am married now, but I was never good on first dates. I too had the lack of flow. You can give it a date or two more and see it the connection is better. I get way more talkative and comfortable with people after a few interactions. In this instance I don't think it would be offensive for you to bring it up. It can be simply a question about it (like when did you start stuttering), and you can see if he opens up about it. It will either lift a weight off of him, and he will be more open, or he's still closed off, maybe he's not the right fit for you.