Emily and Jack's relationship is one of the few relationships to already have begun prior to the events of the first book. They are also one of the few adult relationships shown in the series.
Not much is known about how they began dating and subsequently the details of their engagement and wedding. However they are shown to be very much in love, and have had three children together: Nora, Simon, and Alice.
Jack recruits Simon to help him out with a video for his and Emily's anniversary.