‘The Sexless Innkeeper’
Season 5, Episode 4 - Aired October 12, 2009
After a woman goes home with Ted but spends the night on his couch, Barney breaks the news to Ted that he was just used for a place to crash. Meanwhile, Marshall and Lily are excited to host Robin and Barney for a couples' night.
Quote from Barney
[As Ted goes to his bedroom to be with a blonde woman he was hooking up with:]
Ted: God, I love being single.
Robin: Hey, Barney, you ready for brunch with Lily and Marshall?
Barney: [alarmed] What have I done?