I was thinking about ten leaving Rose at that beach (the second time) and i kinda tought it might be because of River? Not because he couldn't wait to get married with River or some love at first sight, but because he knew he would end up with her. And since there will be wife River, there can't be his beloved Rose, right? I think he maybe kind of figured, that since he will mary River, he either lost Rose again or didn't even get to travel with her again. Yes, time can be rewritten, but who would want to risk that. He's the Doctor, the Doctor who burned up a whole sun just to say goodbye to Rose, he would do anything to get back to her, he would even figure out tentoo, but risking her life? No way. I was thinking maybe that was another reason why he left her and decided it's the best decision after all.
