Alex's comments prompted the show's women to both scream, "Too much skin!" in disbelief, with Allison, 40, branding Alex an "old man".
Karl tried to ease the tension as he sarcastically claiming he agreed with Alex's assessment of the halftime show.
"I thought it was disgusting, all that skin. Not my cup of tea," he joked.
But there was no changing Alex's mind, who stood firm in his convictions, and claimed the racy performance made them bad role models.
"I just thought it was too much. It's sending out a bad message to the young kids," he concluded.
The shock comments come after Karl took offence at a joke made by the Married At First Sight experts about Elizabeth Sobinoff on the show last week.
It's their job to match the contestants up with "the one" - but MAFS' experts haven't seemed to grasp that concept yet.
John Aiken, Mel Schilling, and Dr. Trisha Stratford made a joke about Lizzie drawing the short straw when she was matched with cheat Sam Ball last year, who ran off with Ines Basic.
"That's your fault," Karl quipped!
Fans are hoping Lizzie will have more luck this time after being matched with Curzon Hall.
The latest season of Married At First Sight Australia is proving to be one of the most controversial series of the reality show yet.
An on-set source has told the hosts of Hit106.9 that filming had to be stopped for two weeks because of the escalating drama, and that one cast member was even forced into rehab by producers over concerns for their mental wellbeing.
“Apparently, they've just started filming again after a two-week break because the producers were just like, '’this is going too far, we need to resettle ourselves, take a two-week filming break and then work out how we can tackle the rest of the season,’” host Nick said.