The Big Bang Theory (2007)

S12E12 The Propagation Proposition

Penny unexpectedly encounters her former boyfriend, Zack, who extends an invitation for her and Leonard to join him and his new wife for dinner. After the meal, the newly married couple presents Leonard with a peculiar suggestion that leaves Penny feeling anxious. Meanwhile, Raj is trying to reconcile with his ex-fiancée, Anu, hoping to patch up their relationship.