I’m 19 bf is 24. we have been together for almost a year in june.

tonight i went to walmart and my bf didn’t go in with me, when i got to the car i was putting groceries away. while i was doing that a guy comes up to me and he said that he wanted to say i was beautiful. i said thank you. that was it. my boyfriend heard and got mad and told me i should’ve said i have a boyfriend. i told him i was just accepting a compliment it’s not like he was asking for my number. if he did i would’ve told him i have a boyfriend. i said what’s wrong with me saying thank you and he said you’re a bop, ig meaning like a thot or something idk. but he’s been giving me attitude all night and being cold to me. like am i in the wrong or what?