My fiance's father and mother are separated. The father has been dating someone for a long time. However, my fiance is not a fan of her at all. We are wondering how to process the parents in to the ceremony. The best man will be walking his mother down the aisle. Should his father already be seated, or should he walk in behind them? Also, if he walks down the aisle how do we tell him we don't think his girlfriend should be walking down the aisle with him?