How or should I confront my wife going out with guy when visiting relatives?

[Joseph]

My wife was on vaction visiting relatives and she meets guy and goes to concert. He wants to meet her the next day for lunch or dinner. She does not tell me. Yes, I read her emails because she has done stuff before three years ago and I suspected something. He emails her to be on her facebook. She does not say she is married on facebook. I am tired and just want a simple life. Do I confront her and face the consequences?