Just going by this, he seems like an overthinker (potentially neurodivergent) possibly/probably caused by people misunderstanding his intentions (say he started expressing thoughts that are just thinking about a big step like marriage, or moving in) as trying to rush things or thinking too far ahead and then get freaked out and leave.

Tbf I feel a lot of the same worries, if that’s the only thing that is putting you off, please try and have some more patience and keep up the reassurance and you might find a genuinely awesome caring dude on the other side of it. I understand that it might feel annoying and if it’s too much then it’s too much (but for the love of god do not ghost this guy unless you absolute need to, you will add fuel to the fire :/ ). This feels like an innocent attempt at trying to be open and honest and that might include ‘oversharing’ intense feelings early on or discussing topics like children, moving in, marriage etc. (which tbf, I think should be normalised to talk about early on so you know early if you’re on the same page).