“Psychologists agree that an ultimatum is not a good way to get somebody else to do what you want,” Nick Lachey tells the contestants in episode one of Netflix’s new show, The Ultimatum: Marry or Move On. A strange start, considering the series’ title. But this new “social experiment” by the creators of Love Is Blind takes the idea of an ultimatum and changes the meaning of it completely, suggesting that in order to know if you want to marry someone, you’ve got to try dating other people, from a pool of six, to help you decide. And so, six couples at a crossroads — to marry or not to marry — have signed up to give it a go with the guidance of Nick and wife Vanessa Lachey.