By now, fans know that the marriage between Jack and Rebecca on This Is Us wasn't always easy. In fact, sometimes it seems like it was extremely hard for both of them. But even in spite of those difficult times, viewers have always been able to see the very real love they share in the show's flashbacks, before and after they had kids together. But fans also know that Jack died before their kids even grew up, so how long were Jack and Rebecca married on This Is Us? Even if their marriage was long, he still died way too soon.
In Episode 13, viewers were finally given a glimpse into the past at Jack's funeral, which revealed a general time frame of when his death may have occurred. Since all three Pearson children were clearly teenagers as they stood beside Rebecca at the funeral and they were born a few years after Rebecca and Jack were married on This Is Us, it's safe to say that Jack and Rebecca were potentially married for 20 years or so before he died. The timeline of the show jumps around quite a bit, but in the episode where, presumably, the triplets were conceived, Jack and Rebecca were already married and they still looked pretty young. Though, to be fair, they are just a naturally gorgeous couple.
The rough timeline, according to what characters have said and the clues on This Is Us, places Jack and Rebecca at being married at around 30, since he said in the show that he didn't know what he wanted until he met her at 28 years old. Let's say they married two years later, then spent a few years being kids-free, until Rebecca gave birth and adopted Randall on Jack's 36th birthday.
Then, let's say the kids were all around 15 when he died. That means Jack and Rebecca were married for around 21 years, give or take a couple. It would also place Jack at dying at age 50 or 51 which makes sense, since so far, viewers haven't seen him in any flashbacks looking older than his late 30s, and we have yet to see Jack interact with their kids as teenagers.
But even being married for 20 years, seeing Rebecca lose Jack on This Is Us is going to be all kinds of awful. If no one can handle flashbacks to the funeral, or Thanksgiving meals where she's quoting him, how is anyone going to handle his death? Jack is the TV dad we all want at this point, so just the thought of seeing his on-screen death is hard. No amount of time together was ever going to be enough, but I'm at least glad they seem to have had two happy decades together at least before his tragic passing.