Ted Mosby and Robin Scherbatsky's breakup was hinted at nearly half a season early in How I Met Your Mother. The pair's "will they or won't they" relationship was a major focal point during How I Met Your Mother's nine seasons. Even though it was revealed that Robin was not the "Mother" in the pilot, Ted spent a lot of time pining for her.
After scaring off Robin by coming on too strong during their first date, Ted managed to win her over by the end of How I Met Your Mother season 1. They entered a relationship in the season finale and their honeymoon phase continued into season 2. They tried to tone it down a bit due to the split between Marshall and Lily. The breakup of their friends didn't last long, but in a short time, they themselves were forced into facing the fate of their own relationship.
Ted and Robin officially announced their breakup during Marshall and Lily's wedding reception in the episode "Something Blue". As much as Ted and Robin still cared for each other, they knew they were heading in different directions, so they amicably split. The breakup occurred a few episodes earlier in "Showdown" but the duo decided to keep it a secret until after the wedding ceremony. In fact, Ted and Robin's breakup was insinuated twelve episodes before "Something Blue" during a flash-forward scene at James Stinson's wedding, which indicated that Ted and Robin would both be single a year later.
How Ted And Robin's Breakup Was Foreshadowed
During the How I Met Your Mother season 2 episode "Single Stamina", Robin finally met Barney's brother, James. Barney claimed that he and his brother were exactly alike except for the fact that James was gay and black. It was later revealed that James could no longer partake in frivolous nights out at bars because he was engaged to a man named Tom. The episode flashed forward to a year later as the group attended the wedding of James and Tom. Marshall and Lily left at a reasonable time but Ted and Robin stayed longer. Earlier in the episode, it was stated that single people stay out longer because those in relationships don't have what they called "single stamina". Ted and Robin were already broken up by the time the wedding occurred in the future as confirmed later in the season.
How I Met Your Mother had a history of foreshadowing important events. Sometimes the series would hint at something later in the episode as was the case with the death of Marshall's father. Other times, the sitcom would hint at something monumental like the clues to the Mother's death at the end of the series. Even though Ted and Robin's relationship was short-lived, they harbored feelings for each other for quite some time. Their paths did eventually go in different directions but they found their way back together when the time was right.