Grooms man brining a date the bride does not like?

yea, this is NOT your groomsman's place to invite guests UNLESS you tell him he can. You need to call him RIGHT AWAY and tell him that you have a "guest list" and she is not on it. you are on a tight buodget and you probably have to pay per person for the catering. You have the right to not even give him a reason. Its your big day, not his. Tell your fiance that either you willl talk to him or he needs to but no guests are allowed to be invited without first talking to you. If he doesnt like it, Im sure you can find someone to replace him!