He never went back because he was forbidden to go back. All potential Jedi are admitted to the Temple, but they are not allowed to have contact with their families because of the Code, which forbids attachments and thus contact with their family. When Anakin was admitted, he was told that he couldn't go back home. As to sand, that doesn't mean anything other than he dislikes sand. That doesn't make it his home any less. Again, home is where you have roots. Where you have ties. No, it is because things have changed within him between when he went to war and when he became an agent of evil. All of the things that happened on Mustafar resulted in his becoming truly evil and with Padme gone, he stops being Anakin Skywalker and becomes Darth Vader. He is severing ties to his past because of what it represents. His failure to save his mother and his wife, because he was not as powerful as he wanted to be. He leaves Tatooine again because he went off to fight in the Clone Wars. He doesn't stay because of that. He could have chosen to stay, but didn't because of his duty to the galaxy at large. He still believed in the Jedi Code which placed duty above personal self interest. He placed the welfare of the galaxy ahead of himself clear up until his dreams began.