Found: Book like Heart Goes Last

I have been reading Margaret Atwood's The Heart Goes Last and have strong deja vu of a book I've read before. It's about a couple who are given a box/gift at the beginning of the story and get inducted into a closed society with rules, if they accept or open it. They're not allowed to talk about it to anyone outside the group, and eventually at the end they are given the option to lead/run the society or run away. They choose to run away.

I know the movie The Box has the exact premise. It is based on the short story, Button, Button by Richard Matheson

>2 lowelibrary: Thanks! I've checked it out, it looks really interesting!

It isn't the book I read - some more intense googling has shown me the book was "The Marriage Pact" by Michelle Richmond. :)

Touchstone The Marriage Pact by Michelle Richmond.