If
She knows she's dying because of Elphaba and Nessarose.
Melena wonders if perhaps she should have told someone about her affair.
If she did, Elphaba might be spared the pain of discovering her true father…Of course, she might not find out. Nessarose might have been born later.
Melena might have lived...but then she considers the other side.
Frex would have shunned her if she told. The man she slept with would be angry, terribly angry…
So she does not tell, not even as her eyes start to close forever.
But she still wonders if it's the right thing to do…
It is, she decides.
Then she dies, content with her choice.