Help!! my oh doesnt want my cousins Bf's at the night do

Right at the beginning of the year my mum mentioned about my cousins who happen to be my bridesmaids boyfriends coming to the night do. I said it was an idea but i wasnt sure about it and there was no more mention of it... We were at my nanans small gathering the other month and she apparently mentioned it to my auntie i wasnt there i was talking to other family and my auntie who is their mum and uncle their dad said no dont bother with it... So i thought its dead and buried no more about it. Monday my mum gets a text from my cousin saying they can come now so i asked how come i thought this was dead and buried and there was no more talk of it.

My mum and i have argued all week and so has me and my OH too about it and i cant take no more i dont want them there and neither does the OH and hes said if they turn up then he wont be happy. I dont know what to do i dont know how to approach the subject im incredibly stressed. Help!!!