Don't have less sex, don't have more. If you normally have boring sex, have boring sex with her even if it kills you. And remember, no matter how tempting it is to try out that new trick you just learned, don't do it with the wife. New tricks are a sure giveaway- stick to your old favorites. It's just suicide.
Women talk, women are deceitful, and women confess.
Guilt eats away at her and she confesses to ease her conscience. The better friends they are, the greater the pressure and the speedier the confession. Those are all the possibilities. However, there is a silver lining- if her friends want you, others will too. They just haven't seen you yet.