"Anakin" truly died on Mustafar. He avoided Tatooine due to how associated it was with Anakin. He only visited Padmes grave once in his time as a dark lord.
When he did end up at tatooine he actually gave the order to have Owen and Beru killed as it was a loose end of Anakins life that wasnt brought to the forefront of his mind until storm troopers went to their moisture farm.
Im a nerd i know