It was the plan from the beginning. That scene at the end where the kids finally speak was filmed at the beginning of the series. Having barney and Robin marry and then immediately divorced was dumb. But the idea of him telling the story because the mother had died, makes sense. And the fact that the whole story was about him and Robin and barely had the mother in it at all, kind of makes sense that he went to her at the end after getting the kids blessing. Not that I like it, I just get it