Evidence must include the testimony of a corroborating third party. It is not sufficient for the spouse committing adultery to simply admit the adultery.
In my case: 1.) Disposition (My wife abandoned her car in a parking lot and jumped in car with OM, obviously wanting to hide what she was doing) 2.) Opportunity (My wife spent the entire night at OM's house)
Corroborating third party: Private Investigator
Supporting Evidence: Video/Pictures/Testimony from me
Admissions aren't enough because they may show collusion where two parties are getting a fault divorce by colluding with each other to avoid a state waiting period.
You do not have to show actual intercourse.
"You can't reason someone out of a position they didn't reason themselves into."