Cruise ships host millions of people each year and thousands on a single vessel. While it is a holiday filled with relaxation, comfort and ease – there are a variety of different personalities that make their way onboard, and cruise staff must cater to each of these cruisers needs.

While it can be an enjoyable experience to make sure guests are satisfied, one former senior cruise ship officer Jay Herring told there is a clear “social evil”permeating through the cruises.

In his book, The Truth About Cruise Ships, the former Carnival Cruise Lines employee said some experiences left a sour taste in his mouth, especially amongst passengers.

“For me, there was social evil on board the ship.

“I’m speaking, of course, about rampant infidelity.

“On land, I am probably surrounded by more unfaithful people than I realise.

Jay also noted his wife, who worked abroad casinos on the same ship, saw “multiple affairs in progress every day.”

“It bothered me not just because I witnessed it, or it existed, what bothered me was that it was so commonplace and so frequent that its came to be considered normal behaviour,” she said.

This article originally appeared on Over60.