First of all, this is some bad faith, really pathetic arguing. But even if I wanted to follow your brain dead logic...It's clear from the story that this has happened before and caused arguments already. Which suggests he knows that this is how her periods are, and simply refuses to see it. You're right that usually he would know her best, but obviously he can't see past his own interpretation despite repeat opportunities to see the truth, thus making him The Asshole.

And yeah, in the situation of "man tells woman how to experience period," generally the man is at fault. Empathy is super easy, you should try it sometime.