Permission

“How can you be certain he is the one, if he is the only one?”

Anna (Rebecca Hall) and Will (Dan Stevens) have been together ten years, each the other's first kiss, first love and only relationship. At her thirtieth birthday party, just as Will is about to propose, a friend's drunken toast suggests they sleep with other people before they marry. Brian Crano follows the idea past the joke, and Anna is the one who sets it in motion, proposing they open things up, though she may be the one with the most to lose.