"[…] It had to be Robin. That’s how we felt. When they were together in Season 5 and we broke them up … it was very divisive. Some fans were like, “Great! Barney’s back to being Barney. I don’t want to see him in a relationship.” But there were a lot of people [who were] like, “Boy, I feel really unfinished about Barney and Robin.” We knew at the time that we had all this other Barney and Robin saga up our sleeve. We were at that point planning out what Seasons 6 and 7 would be. We knew that they would have this momentary flirtation with rekindling in Season 7 that we just did, but Robin chose Kevin (Kal Penn). Barney was heartbroken and I think in that moment, people were like, “Aw! Bros, what are you doing to us?!” … Of course, in the back of our heads, whenever we heard that feedback, we were thinking, “Just wait! We’re gonna get to it.” But yeah, IT HAD TO BE HER. They’re a special couple."
— Craig Thomas, co-creator/showrunner, to Tv Guide.
DEAL. WITH. IT.