She was back, but she'd already gone
Robin was back. She was back and she was standing at his door, but he'd chosen bimbos. She was obviously upset and she'd come to him, but there was a blonde tied to his bed. Robin was back, but she wasn't his. She'd taken the ferry back to the city to escape Ted's train-wreck wedding (or maybe to escape him, he wasn't sure which he would prefer). She was back, but she'd already gone.
When they got back to the city, they all went their separate ways. He was busy with the North Koreans (not sulking or moping or watching old Metro News One broadcasts on his Tivo). Ted was sulking and moping and designing some really depressing building that looked like it might actually have a torture chamber inside. Robin was hiding out with Lily and Marshall, trying to avoid Ted (or him). Lily and Marshall were trying, with no luck, to get everyone back to normal.
Lily came to see him one night after a long meeting hashing out the very illegal details for a deal with his North Korean counterparts. She barged into his apartment unannounced and uninvited, not even bothering to knock.
"Lily, what the hell?!" he snapped, jumping up and frantically scrambling to change the channel or turn of the screen or something before she saw what he had been watching.
It was too late. She'd already seen enough to know.
"Barney, why are you watching Metro News One? Really old Metro News One, I might add." She crossed the room slowly as she spoke, as if any sudden movement might set off a dangerous chain of events. He couldn't really blame her for that one. She knew him well enough to know that he was nothing if not thorough, and had he anticipated her quasi-ambush, he would have been prepared.
"Uh, that wasn't Metro News One. Seriously, who do you think I am? That was porn." He was aware that his voice cracked a little with that statement. He just hoped she wasn't quite as tuned in.
She raised an eyebrow, indicating that she was in fact aware of the voice-cracking, and asked, "Robin did porn at her old news studio?"
Maybe he could convince Robin to make porn at her old news studio. Then Lily would have to believe him. But he'd chosen bimbos and Robin had taken the ferry, which is why he was watching her old broadcasts instead of porn to begin with.
He finally just sighed in response and sank bank into his couch, wishing Lily had walked in on him watching actual porn.