I do think, that if nothing else but for appearances, you should do this. Give her an audience, but preface it with "as soon as you start lying to me, this conversation is over."
And then follow up on that.
Then you can tell her family "I tried to talk to her, but she keeps lying to me, and I'm not going to sit there and listen to that -- it insults my intelligence, and it's incredibly disrespectful to our marriage."
