Chris is mostly correct. Foreign Wives says "opponent" and in multi-player the only person that classifies as your opponent (singular) is a player you are currently in battle with. As such, Chris is correct that players not involved in battle can play cards to affect FW (such as Angel of the Lord or Grapes of Wrath), however they can do so even if they have drawn 5 or more cards since FW's ability doesn't refer to them.
