Am I in the wrong here?

My bf is Korean. We are in Japan right now for vacation. We’ve been dating for almost five years now. In the past, whenever we would get gyoza (Japanese dumplings), he would laugh at the way I’d say it and correct me. So last night we went to a gyoza bar and I went to order for us, I whispered to him to remind me how to say it correctly again and he got extremely mad at me and offended. He says he doesn’t know Japanese culture and it made me feel like I was being racist or something. I know they’re two different cultures, I was not assuming he knew because he’s Asian at all, I asked him bc I know in the past he would laugh at the way I say it and I didn’t want to embarrass myself in front of the chef. I was honestly baffled at why he was mad at me. If it was because of a racist reason I completely understand but it was not and it’s because he always made fun of me for it. Am I in the wrong here?