This has gone unanswered for a week. I think it would make more sense to let "known couples" know that they must announce to players that they are a couple. If there are any complaints or suspicious behavior, of course, it should be addressed. I have managed poker games at home and in casinos and some of the best action at the tables were between married couples. Bad reputations have a way of quickly drawing attention to couples that may be colluding. If the other players are aware they are a couple and no one objects...I would let them play at the same table. Telling players they are not allowed to play in your cash game would probably cause both players to leave your poker room. Is that what you want? I don't think so.