Thats a good one I hadn't thought of. It's not like it would be breaking some law, but would absolutly be taboo. But my dad died young in 1980 (7 years before we met) making that an impossible fantasy. But if he had still been alive when we met and married, now that you mentioned it, I would absolutely encourage my wife to let him fuck her. And since my wife is the biggest slut I have ever met, I have no dout that she would have let him fuck her and would have let me watch. As for him...... way back when I was just a teen in the 60's, I knew he was what we used to refer to as a "Whore Master". So yea, he would have fucked my wife in a heartbeat. And he wouldn't have cared whether I knew/watched or not.