After Erik and Lauren embrace a surprising twist, the exes prepare for a new slate of dates and revisit their sweet beginnings -- and somber endings.

The couples reach the end of the "ex-periment" and face a crucial decision. Can love conquer all, or are some feelings better left in the past?

Emotions run high as the former couples reunite for first dates, and "ex-pectations" are tested during an evening of alluring temptations.

A radical roommate exercise leads to a string of emotional letters. Peter shares a troubling secret with Diane. Jeremy faces his toughest critics.

Worlds collide as the exes meet for drinks and candid conversation. Later, a trust exercise proves to be positive for some and painful for others.

The couples trade spaces and establish new sets of rules. Cam orchestrates a high-stakes reunion. Peter struggles with a heated confrontation.

As the couples go global for a series of intimate trips, Lauren fulfills a dream, Cam addresses an insecurity, and Jeremy makes a shocking decision.