Could Padmé have prevented Anakin’s fall?
There is basically zero way Padmé could’ve prevented Anakin’s fall to the Dark Side. Sure, she had experience with his dark temper, but there is no way she could’ve predicted his visions or Palpatine’s influence over him. Yes, she had her own issues with the way the Chancellor ran the Republic, but that was a political and professional matter, not a personal one.
The Clone Wars shows on several occasions that Padmé and Anakin were on very different sides of the conflict. During the season 3 episode “Heroes on Both Sides,” we learn that Skywalker is pro-war while his wife and by extension, his Padawan Ahsoka are anti-war.
Now, whether Padmé was aware that Anakin’s pro-war stance was because of his loyalty to Palpatine is unclear. However, she would’ve known that the pair were very close. It was also evident that she was trying to distance herself from the Chancellor, despite having been the one to call the Vote of No Confidence during her reign as Queen of Naboo against Finis Valorum. She, much like Anakin, had been a pawn in the then-Senator Palpatine’s lust for power.
There are still a load of unknown factors that we still don’t know. Were there other hints to Anakin’s potential fall that Padmé saw but simply dismissed? Where there things that Ahsoka and/or Obi-Wan could’ve told her? Perhaps Rex mentioned something, given he knew of the secret marriage between his general and friend and the senator from Naboo. We’ll probably never get a full picture.
I should also note that Padmé wasn’t Force Sensitive and would not have been able to sense Skywalker’s emotions the way Ahsoka and Obi-Wan would have. Anakin was also known to push his negative feelings away and not want to talk about them.