Children and animals cannot consent which is why I didn't use them, but ok then don't answer. You don't have any answer to provide because if the requirement f

Children and animals cannot consent which is why I didn't use them, but ok then don't answer. You don't have any answer to provide because if the requirement for marriage is any consenting adult who love each other there is no reason to not expand it to multiple people. The only reason would be an appeal to tradition, but that would discount gay marriage.