EXPLOSIVE SHOWDOWN: COUPLES AT WAR!

Melinda and Layton are going head to head with Harrison and Bronte to defend their relationship

Retreat Week should be a chance for everyone left in the relationship experiment to relax and get to know each other better. Instead, the tension between the couples explodes. Will marriages crumble under the pressure?

The trouble begins at the Married At First Sight Australia commitment ceremony, when Harrison Boon - who's married to Bronte Schofield - accuses Melinda Willis and Layton Mills of faking their romance.

"He just knows how to grind my gears," fumes Brisbane beauty boss Melinda, 32. "I feel he was projecting from his own relationship. We were never faking it. Layton and me, our relationship is 100% real."

This week, when the remaining couples go on a retreat in New South Wales' Southern Highlands, Harrison gets into an argument with Evelyn Ellis, which leads to the women, as a group, confronting Bronte about her relationship with Harrison. Bronte is so upset by what Melinda says to her, the online beauty educator storms off in tears.

"I'm not liking what I'm seeing and as another woman, I can't just sit back," explains Melinda. "I need to say something."