Two couples find closeness and comfort, while others struggle with tension and fights. Romance heats up at home for one pair.

Excitement and anxiety brew as everyone forges fresh connections and selects new partners. One commitment-wary person's motivations spark controversy.

From discussing gender roles to rekindling sparks, the couples try to reconnect. One person's lingering emotions casts doubt on two relationships.

After talking through issues from bathroom storage to bedtime massages, five new couples emerge. Now it's time to stress-test a trial marriage.

Revelations are shared during the changeover. Will a one-night stand break one couple — and will someone new come between another?

As one person hits a breaking point and another struggles to process her feelings, a question looms: is love alone enough to sustain a marriage?

After the cocktail hour, some bonds are strengthened — and others crumble. The couples meet with friends and family and spend their final night together.

Shocking updates, hard truths and powerful realizations come to light when the group reunites for the first time since the conclusion of the experience.

After a last night together, the couples begin to co-mingle, looking around for marriage material — outside of their original relationships.

With Ultimatum Day upon them, the couples make their life-changing decisions — who will walk away newly engaged, and who will walk away alone?