Life Happens
It's a simple fact, one that we all know very well, that the universe is a better place because of the Doctor. From the moment he "borrowed" the TARDIS (though she always insisted that she stole him), he had unknowingly begun a journey that would take him to the edges of time and space; to the beginning of life in the universe to the death of the last individuals that ever lived and breathed within its boundaries. And there would be many times that he would risk, and even sacrifice, his life so that we may continue on.
But for all the wonderful things he has done for us, there are still people who pay a terrible price for letting the Doctor come into their life. This is a fact most people chose to ignore but one that many cannot and it is a fact that no one understands better than the Doctor himself.
There are many other reasons that he chose to distance himself from his newest companion, but this is the one that he reminded himself of every time he wanted to hold her hand for a little while longer or breath her in just a little deeper when she embraced him. He reminded himself of it religiously until the day he took Rose to watch her father die and he ended the day realizing he'd made one of the biggest mistakes of his lonely 900 years of life.
It was her tears that did him in. There were just a few of them at first, not enough to smudge her mascara but enough to turn her eyes and nose red. Just enough to tug at his two hearts because she was so incredibly beautiful like this and despite himself, he noticed.
Rose had wandered off, to her room he presumed, and he had let her go. She had needed her space and it was best for both of them if he honored that. But the TARDIS had other plans where Rose was concerned and rather than let him go to the kitchen for a particularly strong glass of Drogarrian whiskey, he ended up walking straight into her bedroom.
He had only been in there once before when he had helped her carry in her bags, but he noticed the alteration as soon as he barged in. Rose was sitting on the seat of a bay window with its bottom pane of glass slid all the way up and there was a familiar London breeze coming through from the other side, filling her room with the sound of the bustling city. The TARDIS had never made anything like that for any of his companions before and he should have felt glad that his old girl was doing such a fine job of looking after their human, but all it did was give him the sudden realization of just how much he had completely mucked things up.
Rose had looked up at him when she heard her door swing open, her eyes wide and wet and by then her make-up was really a mess. With her knees up to her chest and her arms folded over them, it was obvious she had been sobbing away. He had opened his mouth to say something, anything at all, but nothing came out. Instead, her face crumpled again and even more tears flooded her young and innocent features as she spoke.
"I'm sorry," she choked out, "Doctor, I'm so sorry." Her face fell back into her arms and her shoulders shook from the force of her sobs. It took less than a second for his impressive Time Lord brain to figure out that he just couldn't do it anymore; he couldn't keep lying to either of them about the fact that he was completely and utterly wrapped around her finger. It was a snap decision and that very dark and lonely place in his soul reminded him again that he was a dangerous man, but he chose to sit by her side and pull her into him anyways.
He may have been The Oncoming Storm and the killer of his own kind, but what kind of man would he be if he had walked away from Rose at a time like that?
There was no room for romance that night, but she curled into his chest and buried herself in his arms and he spent the night saying whatever he could to calm her tears. Because if there was anything the Doctor couldn't stand, it was seeing Rose Tyler cry.
The weeks continued on, and weeks turned into months, and he became better at making her happy. They were happy and though they hadn't crossed that line, he had considered them together. Rose was his and he was hers and he knew; he just knew they would get there someday.
That someday came for them in a hotel 5 billion years in the future. He was a new new Doctor and they were in New New York and he had slept peacefully for the first time since the war with her at his side. It was supposed to be the beginning of their new new life but he was still the Doctor and not even he could run from the past forever.
He was in love with her. Not in any way he had ever been before either; no, that new body of his responded to hers in ways that his Time Lord ancestors would look down upon. He fed off her smile, soaked up her laughter, and breathed her in every time she was in his embrace. Her happiness became his lifeline and if he were to go without it, he might just wither away.
It wasn't until they were standing on the side of a street and she asked about Sarah Jane that he realized just how deep he'd gotten himself and it terrified him. The intense need that he felt for that woman, that very human and mortal woman, was finally acknowledged by him and his Time Lord instincts kicked in. A terrible mix for one so human-like himself, and his urge to flee had clouded his judgment and caused him to not only betray Rose's trust because of another woman, but he had put her life in danger without a second thought.
He had believed seeing her crying over her father was unbearable. When he found her reduced to the same state again, entirely because of him that time, it was like being thrown into a lake of ice. When she then tried to hide her emotional state from him and ran to Mickey instead, he very nearly sent the TARDIS back in time in order to right his wrong.
Seeing Rose cry was torture. Seeing Rose cry and her not trusting him enough to let him know was worse than any physical pain he had suffered through during the war. He had sworn he felt the burn of regeneration energy in his veins and had almost wished he could regenerate in hopes that his next body might actually be able to give her what she deserved.
We all know what came next. It was an ironic twist; one of the greatest in all of time and space. In order to stop himself from regenerating, he produced exactly what he wished he could have given her years ago; a version of himself that Rose actually deserved. There was everything about him that she loved but something more: mortality.
He could give her everything now; a proper life with her family, a husband who slept by her side every night, little ones of her own, and someday soon, a life amongst the stars once more.
Except life is what happens when you're busy making other plans, or so they say. Rose cried silent, hopeless tears in the hospital bed and the Doctor held her hand, unable to say anything at all. For once her tears weren't his fault but he cursed himself nonetheless. He was in too much pain to be much of a comfort to her, but she squeezed his hand and he climbed up next to her. His long legs stretched out next to hers as she collapsed against his side.
"I'm sorry," she cried, but she doesn't sob. Her voice was small and tired, too exhausted from the events of that day to do much more than weep silently into his chest.
"It's not your fault," he responded and he managed to place a gentle kiss to the crown of her head. He almost said "these things happen" but he couldn't spit out the words because those things didn't happen to them. Send the devil into a blackhole? Sure thing. Destroy an army of Daleks? Easy. They had done that three times by then. Lose an unborn child in a random traffic accident? No, that was never supposed to be their life.
There were many reasons the Doctor had seen Rose Tyler cry in the past, and most of them were because of him, but they had always worked through it. He had always fixed it, made it up to her, earned her forgiveness somehow. But that time was different.
That time, no matter how much he willed the universe to grant him some way to halt Rose's tears, the universes provided no answer. Those things simply happen and even the Doctor couldn't change that.