Last Resort's Carl isn't sure if he had an affair or not.

Since the dawn of married times, the question of what constitutes as cheating has been asked.

For some, the answer is clear cut. For others, though, a change in circumstances can mean a change in meaning. Which is exactly what The Last Resort contestant Carl says happened between he and wife Lucy in recent years.

“I felt like something had to happen,” the personal trainer told The Fix this week ahead of the premiere of Channel 9’s latest romance reality TV show, continuing, “once I’d gone outside the relationship, that was definitely an out.”

Having been together for 12 years, Carl says he and Lucy had "broken up a number of times over the years", adding that their relationship had always been a "very volatile" one. Their problems peaked, though, following the birth of their second child.

"At that time, Lucy and I were sleeping in separate bedrooms and hadn't had sex for 12 months. We made it very clear to each other that, you know, we were only there for the kids and that we didn't really want to be together anymore."

Facing the strain of a failing relationship, Lucy went overseas to visit her family, leaving Carl and their eldest child in Australia. It was during this time that Carl says things really changed.

He sent messages to Lucy instigating a breakup, saying that he felt things were finished, and slept with one of his clients.

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Meanwhile, on the other side of the world, Lucy was determined to give things another go and move forward with their relationship. Eventually, she returned home and the pair have continued to reconcile, but moving past the infidelity has proved difficult for them both.

"I'm still not even sure we should be calling it an affair," Carl says.

Whether or not the rest of the The Last Resort couples will agree, though, only time will tell.

What do you think constitutes as an affair?