Is believing in palm reading considered kufr?

Assalamu alaikum. A palm reader looked at my hand and said I could never have children. I know it's a big sin to go to such people, but it's eating me up inside-how could he say that, and what if it's actually true? Only Allah knows the unseen, so what gives him the right? People around him claim most of his predictions come true. I wish I'd never gone, but I can't undo it, so I'm turning to istighfar (may Allah forgive me). Still, I need to ask: could what he said be real, and how do his guesses work? And if someone believes this stuff, does it make them a disbeliever?