Most agree that This Is Us was one of the most heartfelt and heartbreaking series on television, and Jack and Rebecca Pearson's epic love story certainly had its ups and downs over the course of the show's timeline. The NBC drama series, created by Dan Fogelman, was an immediate hit following its premiere in 2016. Critics and audiences applauded the show for its rich storytelling, pathos, complex characters, and relatable relationship dynamics. Sadly, viewers learned early on that Jack was dead in the present. But thanks to the series' tendency to jump around between timelines, Jack (and his relationship with Rebecca) was still at the forefront of the story.

https://screenrant.com/this-is-us-jack-rebecca-relationship-timeline/