It was 2am in the middle of the Atlantic. An American businessman was raging after losing thousands of dollars in the cruise ship’s casino, a crew member was having a secret liaison with a guest, the ship’s doctor was checking a body into the on-board morgue, and in a tiny windowless cabin a bartender was crying after working 18 hours straight.Cruise ships sell a fantasy of food, luxury and champagne on tap. But this glossy facade sits atop a dark underbelly of illicit hook-ups, outrageous demands from entitled guests and medical emergencies – some of which turn fatal.Recently, the Dutch cruise ship MV Hondius hit the headlines when three of its passengers died of the (thankfully rare) disease hantavirus contracted on board. Illnesses like norovirus are more common, but as a former cruise ship crew member myself, I know how easy it is for these things to spread – and how hard the crew have to work to stop them.For three years, I gained an insight into life on the ocean as a dealer in the casino of a 3,000-passenger cruise liner, sailing everywhere from Alaska to the Caribbean. I witnessed passengers fall in love, heard of others falling overboard, and saw many people behave in ways I’m sure they never would on land.My cruise ship journey started in my early 20s, when I was working in a swanky London casino to pay my way through university. A colleague said I’d earn far more on a cruise, where passengers tipped big and my living expenses would be paid. Plus, I’d get to travel the world for free.Just a few months later, I was boarding a ship in Tenerife for my first stint as a croupier.I quickly learned that the sunsets in Mykonos, opulence in Monaco and turquoise sea in the Caribbean were offset by hard work, long hours and the many VIP guests who lost all sense of normality the moment they stepped on board. Karolina worked on a 3,000-passenger cruise ship for years, which she covers in her new book A very attractive, female guest was once caught trying to leave a male crew member’s quartersTake the man who called me at 3am because the free-flowing champagne had run out in his penthouse suite, and he refused to wait for room service.Another guest launched into a hysterical panic because their designer underwear hadn’t returned from the ship’s dry cleaner ahead of the captain’s formal dinner that night. Meanwhile, laughable complaints about rough seas were a daily occurrence. ‘Could the captain make the ship rock less?’ is a question I was asked countless times. I’d just smile politely.Just as we had to smile at the entitled passenger who believed the captain should turn the 100,000-ton vessel around to retrieve her hat when it blew into the Atlantic.Often the ship was chartered for themed cruises. A week-long nudist cruise departing from the Bahamas – with 3,000 passengers mostly in their 60s wearing nothing but bumbags – was unforgettable for all the wrong reasons. Still, tips of up to £4,000 (to be shared with the team) made up for it.Even on standard cruises, there was never a dull moment. There were the passengers who’d disappear without trace, leaving the crew to pack up their belongings and discuss elaborate theories befitting a bestselling thriller. Had they decided to abandon their old life and start afresh in a Caribbean port? Secretly fallen in love and run off with a fellow traveller?Often they’d simply missed the time to be back on board when the ship was docked in port, but sometimes we never found out. There were rumours of CCTV capturing a missing passenger walking down a corridor, only for them to have vanished when the next camera kicked in.But there genuinely were occasional deaths, peaking at three or four per day on a two-week cruise through Panama, which had attracted a particularly elderly crowd. While these deaths were due to natural consequences of very old age, rules around safety and hygiene are very strict.The moment any seasonal stomach bug such as norovirus is even whispered about, the ship activates its preventative hygiene codes. The self-service buffet vanishes, and public areas, handrails and doorknobs are scrubbed around the clock.But one rule that took priority even over hygiene, safety protocols and security clearances was no fraternising between guests and crew.It was also the rule broken most frequently.I remember a bartender sneaking a female passenger down to his cabin disguised in a life jacket. Another, very attractive, female guest was once caught attempting to leave a male crew member’s quarters in the early hours wearing a baseball cap and oversized hoodie.There’s plenty of crew-on-crew romance, too. Every ship had at least one crew member who’d juggle romances with a spa therapist, stewardess and casino girl around their shift patterns. It always ended with a spectacular meltdown in the crew corridors when the women discovered each other’s existence.Thankfully my own ‘boatmance’ was rather less dramatic. I fell in love with a bartender, and we’ve now been married for almost 20 years.Two and a half years into my time on the ship, a wealthy British businessman and his wife were playing blackjack at my card table on a Caribbean cruise.As an elite high roller, he appreciated my trademark serious approach. He said I should take up the place I’d just been offered at the University of Westminster – before handing me his business card and telling me to get in touch.Six months later, he offered me a job in the oil and gas industry. Later on, I founded an engagement platform allowing online casino players to play together.Today, my focus is on sharing the mindset that helped bring me success, which I document in my new book.While my cruise ship days were turbulent in every sense, it was a gamble that paid off. I found my husband and the path to financial security, too – not to mention a lifetime of juicy dinner party anecdotes.Her Play: Make Your Own Luck by Karolina Pelc (Unicorn, £18.99) is out on June 9.As told to SADIE NICHOLAS