Two pairs of newlyweds wake up in their beds for the first time as husband and wife. The last two couples are matched up by the experts and all eyes are on them as the wedding ceremonies begin.

The four pairs of newlyweds spend a week getting to know each other on their honeymoons. An expectation of romance and intimacy hangs in the air, but not all of the couples are comfortable together.

After knowing each other for only a week, the couples move in together. There's nowhere to hide and emotions run high as they grapple with sharing their personal space on an intimate level.

A dinner party occurs, attended by all four pairs of newlyweds. The couples compare the strength of their own relationship with those around them, but no one is prepared for the fireworks that ensue.

Decision day is just over a week away and the couples are feeling the pressure as they weigh up the strengths and weaknesses of their union. They also face the test of a weekend with the in-laws.

With just 72 hours to go, the couples temporarily separate and avoid all contact with each other while they seek the counsel of friends and family. The stakes are high and hearts are on the line.

The experiment comes to an end as the newlyweds decide: will they stay in their relationships or cut their losses? Two months later, cameras revisit participants to see which pairs are still together.