Extra-Marital Affair [Negligence or Stupidity]

I discovered that my wife of twenty-three years (thirty years’ total) was having an affair with a coworker. I suspect that it’s been going on for at least three years now. Using a digital voice recorder in an effort to confirm my suspicions, not only was the affair exposed by the two of them discussing their sexual activities, I also heard her trashing me relentlessly in every way possible. During their discussion, more or less terrible things were said, which I think not simply incredible but also unforgivable. Adding insult to injury, this happened two days after I was laid-off from a company after thirty-years of employment. Two thirty year relationships ruined within the same week and two days apart, devastating, don’t you agree?
We have been auguring several times a month, which created an uncomfortable environment for everyone involved ever since the affair was revealed. Primarily because despite the overwhelming evidence, she continues to deny the affair alleging that’s not her conversation. As if I don’t know my own wife’s voice; sounds pretty ridiculous, doesn’t it? Additionally, she failed two polygraph tests for infidelity, and yet she continues to lie about the affair despite the significant substantiation of the affair.
Since the incident, I noticed that my wife and her twin sister are constantly whispering to each other about something and when I ask, they simply repudiate such behavior. Most of their whispering took place in the very next room from my location. Little did they know, I can hear them conversing their true intentions. Negligence or stupidity, you make the call? During one conversation, I heard them collaborating about defaming my character so that it would appear as though I’m the root cause for the separation. Their primary focus is to proceed to deceive others with a fake reputation of being good girls and they will do and say whatever it takes, irrespective of how many people they hurt, even if it means holding down the entire ship.
Despite all of this, she continues to claim that she’s innocent and no one believes me, but I’m not that stupid, the separation process is in progress.