Reluctantly, you let them convince you

"But... I'm a man, i can't be your bride's maid"
it's him who answers "Please, Darling. She needs one and none of her friends will be there... Do it for me" he looks at you in the eyes in such a way you're unable to say no to anything he requests
"i-i-i'll do it.. for you" then even if you shouldn'tyou kiss him on the lips for a few "I'll be her maid... only because you'll never leave me aside"
then he smiles and kisses you back, knowing your fate is sealed