In the shocking Dec. 11 episode of Vanderpump Rules, Brittany Cartwright confronted Jax Taylor about his cheating, and he copped to it. Brittany, 28, now says they’re “working on things,” but that work is about to get a lot harder. “There’s an audio tape that will prove Jax is far worse than Brittany realizes,” a source exclusively tells Life & Style. Jax, 38, cheated with Faith Stowers, a former “SURver” at SUR restaurant, and the source says Faith recorded a conversation with him that she’s played for several people in the Vanderpump cast. “Faith recorded Jax saying, ‘I am not sexually attracted to Brittany anymore and I can never see myself marrying her,’ ” the source reveals. “When Brittany hears the audio tapes, she’ll have no choice but to call…