Tragic Irony *SPOILERs*
So Anakin become Darth Vador in order to save Pame, but the reason she dies id because she has lost the will to live or can't handle being the cause of Darth Vador, so him becoming Darth Vador is the reason of Padme's death. If Anakin Never turned then Padme would still be alive and everything wouyld have stayed the same, correct?