Things you should know:
Ted still has found anyone to be serious with. Turns our Victoria (aka Cupcake Cutie) is practically engaged to some guy named Claus. But at least now he can move on. He also finally met his slutty pumpkin from season 1 but it turns out they are as far as any two people can be from being soul mates. So Ted continues to involve himself in Lily and Marshall's relationship and milestones. Hopefully the tide changes soon.
Most recently Barney is with Nora and Robyn is with Kevin, her former therapist and all around nice and understanding guy. So why did the previous episode end with them making out in a cab? Peculiar indeed, of course it turns into them seriously cheating on their respective significant others. And at first they with a bit of prodding on Robyn part that it meant nothing and therefore they didn't need to say anything. But in the end they decide they have to. The only problem is that Barney is the only one who ends up going thru with it.
Why Robyn did spill the beans and run to Barney. Well it turns out as ready and mature Barney has become since their last failed attempt at dating, it turns out Kevin is just more mature and more ready. He has better answers and he loves Robyn. Robyn is incapable of seeing pass her previous history with Robyn, but now Barney knows she's the one. The worst part is that as ready as Barney may seem, his heart truly broke when he saw Robyn return to the bar with Kevin. As ready as he is, he's only half of the equation.
Funniest part of the epi: