A number of fan theories suggest that Jim cheated on Pam during The Office. The couple, played by John Krasinski and Jenna Fischer, was one of the primary relationships on the NBC sitcom. Their "will they or won't they" situation drew in viewers throughout the first few seasons. Jim and Pam eventually got together, married, and had kids but encountered some bumps in the road along the way, which had fans speculating about Jim having an affair.
When The Office made its debut, Jim was clearly enamored by Dunder Mifflin Scranton's receptionist, Pam. Unfortunately for Jim and the fans rooting for the pair, Pam was engaged to Roy. Even after Pam called off her wedding, the timing for them getting together never seemed right. This remained true until the season 3 finale when the duo finally got together. From then on, Jim and Pam served as a foundation of the comedy series. Their love for one another continued to grow, but issues started to arise when Jim took a second job in Philadelphia.
The notion that Jim cheated on Pam arose from the time he spent in Philadelphia. His split time while the couple had two young kids put a lot of strain on their marriage. The theory suggested Jim had an affair while he was at his second job, and the producers helped him cover it up. This would explain why his character was rarely shown at the time. Viewers thought he indicated his affair during the Q&A following the documentary's premiere. Other theorizers believed that Jim had an affair with Cathy during the work trip in Florida during season 8. The evidence is intriguing, but there's no concrete proof that Jim would cheat on the love of his life.
The Marriage Struggles Between Jim & Pam Were Important To Their Arc
Almost all of the evidence supporting the Jim cheating scandal can be debunked. Jim's time in Philadelphia wasn't documented because the film crew was hired to focus on the paper company in Scranton. It wasn't easy for Jim to go back and forth between locations, so it wouldn't have been easy for a film crew. Jim apologized during the Q&A because he realized how much he hurt Pam after watching the documentary. He knew it was unfair how he treated her and how he forced their issues into a public display. This was not meant to insinuate Jim did horrible things out of view from the cameras. As for Cathy, Jim was well aware of her motives and made it clear that he wasn't interested. For this reason, the character disappeared, and that was the end of her story arc.
The point of Jim and Pam's struggles in The Office was to showcase how even a seemingly perfect married couple can hit rough patches. Their marriage was put to the test, but they overcame their issues and came out stronger on the other side. This was an important chapter in their arc on The Office, but there's no reason to believe infidelity plagued their lives. Fischer has shared her belief that Jim and Pam remained happily married, and even if a segment of viewers disagree, there's no reason to believe cheating would have caused them to split.