What made Miss Betsy leave in a huff in David Copperfield?

Miss Betsey Trotwood has become so disillusioned with men after her unfortunate experiences with a violent husband that she wishes to have nothing to do with her beloved nephew, David Copperfield Sr, when he marries a young woman half his age. To Betsey, this is yet another example of men behaving irresponsibly, and she's pretty much had enough of that nonsense in her life already. David wanted Betsey to be the godmother of his child, but Betsey won't play ball.
However, after David passes away, his widow, Clara, is sure that Betsey will put aside her animosity towards her and help out the young family financially. She's just given birth to a baby boy, David Jr, the hero of the story, and needs all the help she can get. But Betsey refuses to help out, angrily storming off in a huff, disappointed that Clara has given birth to a boy rather than a girl she'd been hoping for.