If BA had not been a false truelove and William hadn't been a jerk the song would have had a different ending and would probably not have survived as long.

Barbara came 'longside his bed,
Said "William don't you leave me:
We'll wed tomorrow in the church
And you'll never grieve me."

The first time I became aware of this song was in a book called, I believe, Wilderness Journey. I do not recall the deathbed verse fom that--I was about 10 at the time.