Thank you for sharing your unfortunate experience for the benefit of others. It's regrettable that the pseudoscience of polygraphy has gotten a foothold in your country, too.

Ironically, if you actually had been an unfaithful husband and were intent on beating the polygraph, you could have done so using simple countermeasures that polygraphers cannot detect.

While your marriage might be past the point of rescue, you might want to direct your wife to some of the information available on this website. For starters, you might point her to The Lie Behind the Lie Dectector, especially Chapter 1 (on the scientific status of polygraphy), Chapter 3 (which explains the simplistic methodology behind it), and Chapter 4 (which explains how anyone can pass or beat the polygraph -- something one would think you might have researched in advance had that been your intent).