Why can't my autistic husband EVER be wrong?!

Ethan has just got home from work - he's bought back Malbec and Ben and Jerry's, so I can't be too mad with him...
But, for god's sake, why can't that man ever admit to being wrong?

The conversation went something like this. 

Ethan: 'I had a nice chat with Ava today. She told me she tried to climb a mountain [for context, she's at uni in North Wales - and no, it wasn't Snowdon] but they had to stop because there were a field of bulls.'

Me: 'I had the very same chat with her just now. But I don't think they were all bulls, some of them were cows.'

Ethan: 'No, she's sent me the pictures. They were bulls. They had horns.'

Me: 'Cows can have horns, you know.'

Ethan [loud and self-important]: 'No, Laura, they can't. Only bulls have horns. Cows have udders.'

Me: 'And they can have horns too.'

Ethan [louder and more self-important]: 'No. You have a field of cows with one bull, or a field of bulls.'

[No, I wasn't sure what that had to do with anything either but that's another of Ethan's autistic traits, to chuck something in to conversation which is completely beside the point of what you're talking about.]

Me [looking it up on the internet as I happened to be online, and reading from the screen]: 'Both males (bulls) and females (cows) have horns.'

Ethan: 'Yeah, that's not talking about actual cows, is it?' [What??] 'You need to see an actual picture.'

I am now frustratingly invested in having to prove to Ethan that cows can have horns, when initially I was just going to let it go. Simply because he's so bloody annoying and can't ever admit he's wrong about anything and is always so bloody pigheaded and man-splainy about everything, even when he doesn't actually really know what he's on about, which is so annoying. So now I'm looking up images of cows with horns - which I sucessfully get on screen, dozens of the things, just as Ethan says...

Ethan: 'But they'll just be tiny horns, like, little nodules...'

He sees my screen

Ethan: 'I don't think they're cows, they're a type of cow-bull'

AAAARRRGGGHH!!

Knowledge is not power

I know, by the way, where this insatiable need to always be right comes from. There's so much in life that he struggles with and doesn't understand - things that seem to come easily to neurotypical people - that he always feels he has something to prove (to himself as much as anyone else) and his already fragile self-esteem can't ever admit to being wrong. 

But to be married to that constant wrongly-placed 'rightness' is so, so frustrating.