Toi:
I apologize if I came on too strong, but I do tend to get very sore when I feel that people are making blanket statements along the popular assur-until-proven-muttar line.
Obviously, there is a CHANCE–however insignificant and infinitesimal–that any woman other than one’s wife may end up being the catalyst for infidelity, but that is why God gave us brains and a yetzer tov. One needs to be intelligent about things.
Yes, I don’t deny that a woman who has spent years of her life involved with couples is bound to have encountered horrible situations that may have begun at a Shabbas meal, but that’s just my point: this isn’t the sort of thing we have the right to judge based on a perceived “majority” or “percentage.” Every case is different, and every Shabbas guest is different. Again: God gave us brains for a purpose, and He also assigned us the mitzvah of hachnosas orchim.
I sometimes fear: how far will we forbid every action outside of learning for fear of encountering the opposite sex? Maybe we should never visit our rebbeim or roshei yeshiva because their wives or daughters might be home. Maybe we shouldn’t shop for Shabbas because women might be there. Maybe we shouldn’t let our daughters invite their friends over or, chas v’shalom, host B’nos in our houses because, you know, girls.
There is nothing wrong with a personal geder or two–we are all entitled and encouraged to make them. I only bristle when people attempt to impose their personal gedarim upon world Jewry.