My partner tells me something similar. That I make long pauses when I speak, that he's usually right in his guessing and that not doing it is insanely stressful. It sounds incredibly frustrating, to be fair, so I'm trying hard to not be annoyed at what I, as a gut reaction, perceive is rudeness.
The thing is, that doesn't really line up with how I experience it. I feel I get interrupted between words and it seems like I have to then pause and correct him more often than say "That's right!" (Something I'm trying to do when he does guess correctly instead of getting annoyed at being interrupted).
So I wonder if there's a common element in ADHD people thinking neurotypical people are talking much slower than the neurotypical perceive they are and if the instances of being incorrect feel more inconsequential or perhaps the instances of being correct in guessing are very validating in some way.