Escape Artist

Here are some of my thoughts on the whole thing:

Ted has loved her from the moment he saw her and went through so much to be with her. Barney didn’t love Robin for several seasons and he banged so many women up until then.
Ted and Robin worked together, they were natural, fun and sexy, even when they broke up they still clearly loved each other. Barney and Robin were too forced and so unsure all the time, in the end they were miserable together.
When Ted and Robin broke up it took some time for Ted to deal with it but when Barney and Robin broke up he just started sleeping with as many women as he could.
Just because Robin isn’t the mother doesn’t mean Ted doesn’t end up with her later on. I think Ted marries some other women, has children with her and they divorce, later he marries Robin. He calls her Aunt Robin because at the time of telling them the story that’s how his kids know her and at the end of the story he tells his kids that he’s sorry it didn’t work out with their mother and how after some time he’s realized he still loves Robin. That’s how I’d do it if I were the writers.
Ted and Robin are the Ross and Rachel of HIMYM, Barney and Robin are the Joey and Rachel.