"Do not be alarmed. This is a kindness."
Those words continued to haunt the Doctor's dreams … when he allowed himself to sleep, that is. Truth be told, he was afraid to close his eyes, afraid to see the old Amy's hate-filled glare directed at him.
He just couldn't seem to get it right when it came to his mad impossible Amelia Pond. He was a constant disappointment, always letting her down. Sometimes he wondered if it might be better had he never crashed the TARDIS – however unintentional it was – in her backyard. He immediately dismissed these thoughts, though. After all, hadn't she been the first person he'd met in his newly-regenerated body? That made her special. Ever since the night of fish fingers and custard, their lives had been intricately woven together like a tapestry. Were one thread to come undone, the entire picture they had created would collapse.
Amy was a part of him, that much was certain. He couldn't imagine life without her – he didn't dare. Still, that niggling doubt in the back of his mind, that insecurity that threatened to overwhelm him at times – everything pointed to the fact that she could do so much better than a madman with a blue box. She may have chosen Rory as her husband, but there were times when the Doctor thought that he hadn't picked her to be his companion – she had picked him.
The Doctor often felt unworthy of her. How many times had he kept her waiting, after all? And what would happen if, one day, he never came back? Would she turn bitter, as the old Amy had? Would she hate him, as the old Amy had? Though that Amy had been as real as anything, the Doctor couldn't help but hope that his Amy – the one currently safe in bed with Rory, her husband – would never look at him the way that old Amy had. He didn't think his two hearts could bear it.
Yet he knew that day was coming – and soon. Though Amy continued to believe in him and his ability to save everyone, it was that faith that would eventually be her downfall. At which point, he would be forced to let her down so completely that she might possibly never recover. Certainly, she wouldn't want to travel with him anymore. And that was better for everyone, all around. She was too precious for whatever torturous end she would meet were she to stay. In any case, she would be safer leading a peaceful-but-boring life in Leadworth. Specifically, she'd be safe from him. And her safety would always be more important than his emotional attachment to her.
The Doctor turned back to fiddling with the TARDIS, making adjustments and whatnot, as he sought to take his mind off of what was soon to happen.
One more trip, he promised himself. And then it's bye-bye, Ponds.
He only wished that doing what was right didn't have to hurt quite so much.