"I wanted a family, I wanted kids, I wanted the dream, the house... I got it, had it all.”
He added, "There were a few things I knew weren't quite right, but I thought I could change that and help that, mend that... I couldn't do it.”
Sam added that it was a chat with his mum, Julie, which made him realise the marriage wasn't working.
“I said to my mum two years in, I said ‘mum, is this right?’
“She said: ‘Sam, you’re just never going to make her happy, I don't know how you've done two years',” he said.
“I said, ‘I've got my kids, what am I supposed to do?’ - I didn't know what to do.”
In a piece to camera, Sam continued: “It's best we're not in a relationship together. It's sad and upsetting, but also it's just life.”
Following the shock admission, Phoebe posted a snap of herself and the former couple's two children, Poppy and Billy.
“We come in a pack of 3," she captioned the snap, seemingly taking aim at Sam.
"I can’t actually remember the last time I was by myself - for longer than a bathroom break that is ….. & even then it’s a total mission to sneak away …. we wake up together, we go to sleep together and everything in between. Eat, sleep, scooter, picnic, pack it up, repeat,” she wrote.
It's not the first time Sam has spoken out about his marriage on SAS Australia.
He previously revealed during an interrogation that he had cheated on Phoebe during their four-year marriage.
“I embarrassed my wife,” Sam said.
“I had an affair with a woman in Melbourne, it’s true. I was away on tour and regretfully that happened, which would have been a tough place for Phoebe to be.”
The 32-year-old took to social media to share a screenshot and a link to a PDF book titled Charmed and Dangerous: A woman’s guide to reclaiming a healthy relationship.
“We hope this sharing of information may assist you in your journey to achieving and maintaining a healthy relationship; a relationship based on trust, respect, positive communication, honesty and balanced power,” the introduction read.