Answer: Newlyweds
The first time in which Juliet and Peter are seen, is at their wedding, and some of their closest friends and relatives are attending. Peter's best friend, Mark (played by Andrew Lincoln), pulls out all the stops as his best man and films the event. Some time later, Juliet visits Mark regarding the video, since the professionals they hired for the wedding did a bad job. It is then that she realizes that Mark has been in love with her for some time, and has always kept himself at a distance because of his feelings. On Christmas Eve, Mark arrives on their doorstep and presents Juliet with a message (on large cue cards) without Peter knowing. As he leaves, she gives him a kiss and returns to her husband. The three of them are seen in the end of the film at Heathrow, picking up Jamie and Aurelia. While Peter and Juliet are still together, Mark is trying to cope for all of their sakes.