Emotions are high--and sparks fly--as the couples part then embark on the ultimate love challenge. Can they pick a new partner, with real potential?

Will attraction evolve into deeper connection? Selecting a live-in match makes for flirty fun--and hurt feelings. Time for a life-changing choice.

One shock follows another as an honest, tearful outburst leaves everyone speechless. Later, the accelerated trial unions kick off with pillow talk.

Love may be blossoming, but jealousy gets in the way. We're moving fast, so meet the racer dad. The truth stings as everyone trades notes over drinks.

After an evening of strained cocktail hours, couples cuddle--and implode. A forbidden meeting ends with drama as short-term spouses push each other.

Major feelings emerge at the changeover. Everyone's back with their original partners, but the transition might be bumpier than anyone ever imagined.

Tears tarnish a bachelorette bash. Longtime loves try to listen and hold on to hope. The couples board the party bus to bond, awkwardly, at a winery.

An all-nighter deals a blow to a fragile relationship. Can bruised feelings be soothed by a temp partner? Family weigh in with love on the line.

Ultimatum Day arrives. Now the couples must decide whether they'll marry the love they know, reconnect with an attractive alternative — or walk away.