In the movie Last Night (2010), married couple Michael (Sam Worthington) and Joanna (Keira Knightley) Reed lead a complacent relationship until a night out at a dinner party leads them to have a relationship altering conversation about Michael's apparent attraction to his coworker. Though they are able to reconcile before his departure on a business trip with the coworker he was attracted to, Joanna's lingering skepticism sends her down her own path of relationship sabotage when she runs into an ex, whom she still carries a torch for. Both Michael and Joanna are not only forced to confront their own truths about attractions to other people, but are also given the opportunity to act on those feelings. The end results seemingly give away who was more willing and able to honor their relationship commitment.
In the beginning of the movie, it is clear that something is off between Michael and Joanna. What it is exactly remains unknown until they arrive at a dinner party and Joanna assumes a jealous disposition. However, it wasn't until they arrived back at their apartment that Joanna finally voiced her concerns to her husband; sparking an eyeopening discussion between the couple. After they seemingly made up and put the argument behind them, they both were clearly hurt by the other person's insinuations. This set the stage for division and conquer: Michael went to Philadelphia with his coworker and cheated, despite his initial hesitation, and Joanna ended up spending an inappropriate night out with her ex.
By the end, two things were very clear about Michael and Joanna's relationship: they were in a habit of tip-toeing on egg shells around each other in lieu of telling each other the truth to the detriment of their foundation, but equally important, they could so easily be open and brutally honest with the people that they shared their indiscretions. Michael and Joanna said all the right things to each other, but their actions spoke louder than their words. They didn't honor their commitments to one another and although the end of the movie was open to interpretation-- so we don't know what happened with their relationship-- we can still benefit from watching their mistakes. If you make a commitment, relationship or otherwise, honor it, or move on.