DEAR HARRIETTE: I'm getting married soon. Planning the wedding has been stressful for a lot of reasons, but one of the main reasons has been my fiance's groomsmen. One of the groomsmen's girlfriends is extremely jealous and does not want him walking down the aisle with any of my bridesmaids. She is demanding that her boyfriend walk down the aisle alone. My fiance has tried to resolve the issue to …