my friend keeps on telling me that im being groomed

im 18 and im dating a 21 year old man, and my friend keeps on annoying me and telling me that i'm being groom he called my man a groomer even though he never met him, its just annoying me so much.

i told him that im dating someone because i thought he would be supportive because i told him that im happier with my man now bcs he knew much i struggled with my ex

i just don't know what to do i dont want to cut him off he's my best friend and he helped me so much before b but even if i tell him that no i don't think i'm being groomed he won't believe me and would just stick to his opinion though it's his opinion, i dont want him to call my man a groomer he's the best man in the world

idont think we have a crazy age gap so idk any advice is appreciated

ps im sorry for not adding this sooner but my friend is gay