No Padme never knew before her death that Anakin was Darth Vader. This was a closely guarded Imperial secret. Palpatine had just publicly declared the Jedi Order to be traitors to the Republic and then the Empire.
You have turned to the dark side! You're not Anakin anymore! Does Padme know the name Darth Vader? In "Revenge of the Sith," Padme knows that Anakin has fallen to the Dark Side (she must know from his choking her).
Padmé was well aware that Anakin had committed dark crimes that would've started his fall to the dark side. He even confessed to her that he had massacred an entire Tusken Raider village to avenge his mother, leaving no one alive.
When Obi-Wan emerges from her ship, Vader accuses Padmé of betrayal and uses the Force to choke her into unconsciousness. After Obi-Wan defeats Vader in a lightsaber duel, he brings Padmé to the secret asteroid base Polis Massa. She dies soon after delivering twins, Luke and Leia.
Anakin does not have even the slightest bit of remorse. By the end, he feels nothing but anger. Although he feels regret for killing Padme, he still helps the evil Emperor. The film ends with Anakins standing side by side with the man on whose behalf he has committed all his crimes.
Had Anakin not converted: Padme would have been killed by the Emperor before childbirth, and before Anakin and Obi wan returned from the mission to destroy general Grievous. Regardless: order 66 probably still would have happened since the army was under control of the dicator in Palpatine.
Even if he thought Padmé betrayed him, ultimately he felt it was Obi-Wan's fault. Basically, Anakin never stopped loving her, even when he got burned after fighting with Obi-Wan, even when he was reborn as Vader.
This is confirmed later in the movie when Obi-Wan informs Padme that Anakin killed them. Both are torn apart with hurt and confusion, trying to make sense of something so terrible.
After Padme died, Anakin had already fully committed to the dark side. Even if he still desired to do good, his anger had corrupted him to the point of no return.
In the main Star Wars timeline, of course, Darth Vader's attempts to resurrect Padmé on Mustafar were doomed to failure. But it's fascinating to speculate what would have happened had he been successful. In that scenario, Padmé Amidala's return from the dead would not have provided the solace Darth Vader sought.
Although the decision to turn to the Dark Side was Anakin's alone, the choice did not come from thin air. His natural prone to impulsivity and emotion without the support systems he needed in place made it easier for Anakin to stumble down a path of darkness.
However, when they next met in Star Wars: Episode II – Attack of the Clones, Anakin and Padmé's feelings for one another grew into something resembling love, and their wedding at the end of the film solidified their relationship as one of the most important romances in Star Wars history.
The story is Anakin was manipulated to the dark side by Palpatine based on fears of losing Padme and appeals to his desire power and agency, over his life and the galaxy as a whole.
Reva knows that Anakin Skywalker is Darth Vader because she was one of his targets—a child—during the Order 66 killings that took place during the events of Star Wars Episode III: Revenge of the Sith.
The Darth Vader marvel comic series that takes place post "A New Hope" is when he realizes that Palpatine was lying to him.
It served his purpose to pervert and taint Anakin\Vader beyond the point of redemption. Padme was the one thing that connected Anakin\Vader with his humanity - as such, Palpatine could not allow her to live.
Giving in to his feelings, Anakin cuts off Mace Windu's hand, giving Palpatine the opportunity to kill him. Anakin regrets this almost instantly, but the thought of Padme was stronger than his remorse This is the moment Anakin officially became Darth Vader and led to serious issues in the Skywalker Saga.
While Force healing could have saved Padmé, material from both continuities explains why Anakin couldn't use it. The Force is a fundamental omnipresent energy that can be used as “powers” by those who are trained to tap into it. One such power is healing oneself or another at an enhanced speed.
Because of Anakin's attachment to his wife, her potential death was the perfect excuse to step in and make false promises about the Sith. Palpatine even offered a way to save Padmé, and that the Sith could help preserve life. Of course, he never intended to save her, as she'd complicate his plans for Anakin.
After all, keeping Anakin as Darth Vader relied on him believing he killed Padme, so the Emperor needed to make sure no part of the funeral suggested otherwise.
At some point after his transformation into the armored Darth Vader, Amidala's husband, the fallen Jedi Knight Anakin Skywalker came to visit the mausoleum, stricken by grief and remorse for his part in her death.
No she didn't regret marrying him. She regretting not being able to save him. She still loved him, still believed (RIGHTFULLY) that he would return.
We go for the more simple answer, further considering the details of the question itself. If Anakin didn't go into that chamber as the Jedi confronted Palpatine, then Mace Windu would have defeated Palpatine, killing him. If you remember, Mace had him. He was ready to kill him.
The canonical comic Star Wars: Darth Vader #7 confirms the younglings' deaths caused Anakin grief, self-loathing, hatred and pain, fueling his descent even further into the dark side. Those negative emotions also power the dark side, meaning Anakin likely felt stronger as he killed the younglings.