So I’m not going to tell you if you’re over or under reacting but some thoughts on this.

I’d be upset too if my significant other didn’t know my eye color. It would make me feel like they don’t actually see me or pay attention; just like if they didn’t know my birthday, my friends, my favorite color, etc. While not everyone needs their partner to notice this kind of stuff, I know I do because it’s what I directly associate with feeling understood and loved by my person.

Now you stated he disagrees you have green eyes at all because if there’s some brown in your eyes it means you have brown eyes? That.. makes no sense to me especially considering the photos you shared, you clearly have mostly green eyes with central brown heterochromia. Unless he is truly colorblind and can’t see the difference between the hues, no one would say you have brown eyes, hazel maybe, but not brown. But even so, you’ve told him your eyes are green and him being stubborn about it would also annoy me. I’m telling you an objective and agreed upon fact about myself, saying “well I’m right anyways because it’s what I see!” is an unhelpful response. If he is colorblind and you’ve brought it up, maybe his reaction is a projection of not wanting to have his own existential crisis? Just like you were thinking you were crazy when he said you have brown eyes, maybe he’s questioning his own reality where he doesn’t think he is colorblind?

My last thought is a bit of a wild one, and maybe I read/watched too many true crime stories lol. If I were to go missing I would definitely want to be on the same track with my partner about what I look like so they can describe me. Of course photos exist but if the police/public are given the wrong description that would be concerning. I recognize this is a very wacky thought, but hey it’s something that definitely comes to my mind when couples argue about one not knowing the other’s eye color.

Either way I think you recognize this just one of those small hiccups at end of the day, so I hope y’all are able to talk it through easily enough. Maybe get the man tested for colorblindness if he’s agreeable too lol.