Just my take on things, but since Anakin is so impetuous, I think he didn't really comprehend and think through everything until after Mustafar, hence the tears. Yep, I think that too. It was on Mustafar after the slaughter where he put 2 + 2 + 3 + sq root 2 together. The Palps plot lines were fairly involved when you think about it. We as the audience and have the benefit of knowing all the details of the big picture, but Anakin and the Jedi didnt. Thats why I think that if Padme hadnt gone there or if Obi-Wan waited to pursue Anakin, he may have turned back. The line he said about "HIS" Empire may have been retracted too when he really thought about it and decided it really isnt that great of a job.