My [20F] boyfriend [20M] can't stop pretending to be British.

Our relationship is practically perfect. We're soul mates in every sense of the word, we've been together for a while now, discussing living together. But there's this one small thing that drives a wedge between us - my boyfriend just wants to be British, I guess?

It's been going on for so long now and it's getting annoying to an alarming degree. He went to the UK one time and never stops talking about pork pies and how all grocery stores are gross compared to Marks&Spencer (I thought it was a clothes store only??). He only makes Nigella Lawson recipes and looks down on my "americanized" versions of sausage. He's weirdly racist against Irish people and passes it off as a joke most of the time though.

Every time he sees a mention of a British thing, "Co.uk" on a website or reads the word "blimey" he starts reading it in British, although his accent is normally a version of a generic ESL speak, just like mine. Like I know it seems very small and a stupid thing to get mad at, but it's just so weird and "posh" and whatever. I feel awkward when it happens and especially in front of my parents. As an answer to this I started casually mentioning the "bri'ish people aren't real" memes and he actually stopped talking to me because he thinks I'm ridiculous and he's not doing anything strange.

I love him so much and I don't want this to be an issue at all, but it is. How do I go about telling him to stop doing this??

TL;DR: Boyfriend pretends to be British although he's not. I'm going fucking insane. Please help