Yes, cheating exists, always existed and will always exist.
But in the West women are celebrated for cheating and the man is blamed for the cheating (e.g. he didn't sexually perform well enough and the poor woman was forced to do it). Males are even shamed for leaving a cheating spouse.
In the 50s men got cheated on, but this happened rarely (as compared to nowadays) and if the whore got caught it was the end of her social life, nobody else would want to engage with her (unless he hit rock-bottom) and without a male that provided for her she was basically condemned to a life of poverty/misery, that risk existed. In Islamic countries or many other even more traditional countries it was even a matter of life or death.
Of course cheating existed, but it was rare/frowned upon. The same as sexual deviants/paraphiliacs - they always existed, but weren't a mass phenomenon. Comparing this state of the world with the modern one is like saying "Diseases always existed and people died due to them" during the middle of the pest outbreaks, not comparable due to case numbers alone.