Yes- tell her relatives! You need to expose this dangerous affair to everyone and anyone who will listen- ESPECIALLY the people who love your wife.
It's hard to do (at first- the more people you tell, the easier it gets), and yes, she will be angry. But you'd be doing it out of love. She's going down the wrong road, and it's like an intervention. You NEED to get her relatives (all of them) on board.
Me-29 H- 28 Together for 6.5 years 2 kids, ages 9 and 5 D-Day: July 15, 2010.