Natalie's words leave Collins' 'heartbroken' as a fiery showdown explodes in the first Commitment Ceremony of MAFS 2024

Natalie and Collins have had quite the rollercoaster journey on Married At First Sight.

The pair married, left the experiment and returned with hopes to make things work – and it's only been two weeks.

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In the first dramatic Commitment Ceremony of the season, the couple in crisis faced the experts – and each other – in a moment of uncomfortable truth.

But as the truth was exposed, so were untapped emotions and a fiery showdown between one expert and Collins left the groom speechless.

Then, Natalie's shock confession left her husband "heartbroken".

Catch the biggest moments in the videos above.

As the couple sat on the couch, expert John Aiken skipped the niceties and asked Collins the hard questions straight up: "What affection have you showed Natalie?"

For the first time in history, Collins was genuinely lost for words.

EXCLUSIVE: Collins reveals he was once in love but it all went 'horribly' wrong in his MAFS audition tape

Collins felt that Natalie's grief after the recent loss of her father was a "huge factor" behind their inability to be present in the experiment.

John asked Collins to "put the grief aside for a moment".

But that's where Collins drew the line. "I'm sorry, but I don't agree with you," he clapped back at John. 

And in a fiery start to the season, we had our first participant versus expert showdown.

"John, let me tell you something..." Collins began.

But John was quick to remind Collins who runs the couch sessions. "I haven't finished talking," he scathed in response.

The groom and expert went back and forth in a jaw-dropping moment that needs to be seen to be believed.

Lucky for you, you can watch it all here:

Then came Natalie's bombshell confession.

"I don't trust him," she told the room about her husband. "The answers he gives... I feel like he's just giving me the answers he thinks I want to hear."

EXCLUSIVE: Jayden reveals what went wrong in his past relationships in his MAFS audition tape

Collins couldn't believe the words coming out of Natalie's mouth, and you can hear everything she had to say right here:

"My feelings are there for Nat," Collins plead to the experts.

But Natalie had made up her mind, or as Lauren so accurately observed: "She doesn't buy it."

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With that, Natalie chose to 'leave' the experiment, a decision that left Collins "absolutely heartbroken". 

"I don't know what I've done or said to lose that trust," he said with his head in his hands.

Collins revealed he wanted to stay, and so their rollercoaster ride continues for another week. Hopefully they can make things work!

Married At First Sight continues Monday to Wednesday at 7:30pm on Channel 9 and 9Now. Catch up on 9Now.