Season 9, Episode 2 - The Separation Oscillation
Aired September 28, 2015
As Leonard and Penny struggle with the revelation he kissed another woman, Leonard goes to meet the woman in question, Mandy, in a bid to show Penny there's nothing to worry about. Elsewhere, Sheldon films an episode of Fun with Flags alone following his break-up with Amy, who is angered by Sheldon's thinly veiled comments about their recent split.
Meanwhile, Bernadette is uncomfortable with the fact she's known about Leonard's kiss for two years after Howard told her, while Raj is unhappy that he did not share the gossip with him.
Season 10, Episode 21 - The Separation Agitation
Aired April 13, 2017
Howard and Bernadette struggle to leave Halley in day care when Bernadette's maternity leave is over. Meanwhile, when Bert introduces the guys to his new girlfriend, Rebecca, they question her motives.
Season 11, Episode 14 - The Separation Triangulation
Aired January 18, 2018
Raj gets caught in the middle of a domestic dispute when he learns the woman he's dating, Nell, is still married to her husband, Oliver. Meanwhile, when Sheldon rents his old room back so he has a place to focus on his work, he annoys Leonard by being the perfect tenant.