"The Platinum Rule" is the 11th episode in the third season of the television series How I Met Your Mother and 55th overall.
[1] Ted announces to the group that he is planning on taking out his tattoo removal doctor Stella to a movie and is immediately met with disapproval.
He uses examples of Marshall and Lily getting too close to a neighboring couple, Robin dating a fellow news anchor and himself having casual sex with Wendy the Waitress at MacLaren's Pub.
The eight steps of the process and the group’s examples: Even after all three experiences are fully recounted, Ted still decides to go on his date.
Future Ted reflects on the "Platinum Rule" and suggests there is a ninth step: Co-Existence, as we see the other members of the gang begin to do so with those they dated (except for Barney, who still believes that Wendy is trying to kill him).