How does it end?
Barney marries Robin:
BTW, Barney was the sole decent character on this lame sitcom (*).
The mother is this random girl:
Apparently, no one heard about her before the last episode.
The unfunny tall guy becomes a judge. And who cares what happens to his girlfriend (or wife)?
The guy who spent the whole sitcom searching for the mother, marries the mother. That is it. THE END!
(*) Whoever invented this word was being sarcastic. It does not mean “situation comedy”. It means, “sit on command”.