What is Anakin Skywalker's Motivation to Remain Darth Vader?

https://www.youtube.com/watch?v=Q1shS90thpA

I don't know. Employment? 
Heh, it's not like the Jedi are hiring anymore.
Plus, the Empire probably has good health coverage, which is important if you're on life support.

He blames the Jedi and the Republic for Padme's death and so wants to stamp them out. He's also arrogant and power-hungry and being Palpatine's number two provides that for him.

So why would he remain a sith? What motivates him to evil when the driving force of that decision is taken away?

"but I'm re watching the entire movie library and the shows... and I just don't get it? "

It's normal : I had the same problem too when I didn't know much about Star Wars, I didn't get it.

I thought there was a problem with me, I was a confused soul wondering the Earth asking "what is wrong with me" ?

Then I met some Star Wars fans and I realized the problem was not me, it was the prequels: all the Star Wars fans were as lost and confused as I was, actually for them it was a lot worse !

To me nothing made sense but it didn't HAVE to: I didn't know squat about Star Wars so I didn't care.

But for THEM it was a real tragedy: they had 3 excellent movies that made sense and now they had to deal with 3 horrible ones that don't make any sense and also ruined the three previous ones.

It's not your fault: no sane and intelligent person can understand these movies because they were made by an insane person for an unintelligent audience (children below 5 years old).

Don't worry, there is nothing wrong with you: the movies are wrong, and the people who defend them are complete idiots so you shouldn't care about their opinion (if they like movies intended to be liked by toddlers they are obviously stupid, ignore them).

He has a codependent personality disorder.

Very good question though.

I think its more that he had no motivation to change out of Vader.

Also what I don't get is, why doesn't Anakin reject Palpatine the MOMENT he realizes that Palpatine orchestrated the Separatists and the Republic, and was also the Dark Lord that was killing the Naboo in the Phantom Menace. "my people are dying, Senator" -Padme.

I mean, Palpatine was targetting Padme for like 10 years straight and for some reason Anakin doesn't do any investigation into this. Instead he follows Palpatine for no reason at all, instead of lobbing off his head.

Anakin Skywalker, turned Darth Vader, had NINETEEN YEARS between III and IV to ponder what had happened to Padme over the course of Phantom Menace and Attack of the Clones, and everything in the Clone Wars, and then III. Instead, he doesn't do anything about Palpatine, and only remotely considers taking out Palpatine in the now non-canon Star Wars - Shadows of the Empire. (eff u Disney)