With mixed seating, inevitably, you will have men sitting next to — and shmoozing with — someone else’s wife.
That’s why I actually seat the guests in their specific seats, not just the tables. I make sure that singles and bachurim are only sitting next to ugly people or those with poor hygiene and the married people can sit with each other with an opposite sex sibling between them and the next couple. All improperly dressed guests are placed on the other side of a divider at the back of the room. It has worked well for us this way.