And then they let her jump higher and higher and she ends up falling off the horse and dying.
The death doesn't pull Rhett and Scarlett together; instead Scarlett tells Rhett that he's murdered her baby through his indulgence and he tells her she doesn't like any of her children and they just make each other more miserable.
Rhett doesn't want to bury Bonnie because she's afraid of the dark, so he lights candles around her and says he'll shoot anyone who comes in if they try to bury her.
This is all told through Mammie, by the way, who's relating it all to Melanie.
Melly goes to Rhett and gets him to leave Bonnie's side and allow the funeral the next day.