We're falling through space, you and me, clinging to the skin of this tiny little world, and if we let go… That's who I am. Now forget me, Rose Tyler.
He'd said that, at the beginning. Before she saved the world with gymnastics, before he asked twice. Before the end of the world and chips and Christmas in Cardiff 1869, not Naples 1860. Two trips and a few days in a ship that was bigger on the inside and she knew, oh she knew, right then and there she would never forget the Doctor. Two trips and a few days and she was in love, though she would've never admitted it, didn't even know it yet herself.
I could save the world but lose you.
She had made an impression on his hearts already, with just two trips and a few days in the TARDIS under her belt. So when he blew up 10 Downing Street, he hugged her close to him, not wanting her to be lost, so soon. Because she would be lost, eventually. She'd leave, or she'd wither and die and he'd still be here, alone. So he couldn't get too close, didn't dare, because the pain of distance would be nothing to the pain of losing her.
What use are emotions if you do not save the woman you love?
He didn't love her. Couldn't love her. It was obvious, I mean, talk about being way out of her league. He was a 900-year-old alien that traveled through space and time, and he could have anything and anyone he wanted. Course, that did make her question why he was traveling with her, then, out of the whole universe to choose from, but she was sure he just wanted to give a useless estate chav a bit of a perspective on how tiny she really was. But, she couldn't help but wish for more. So she brought Adam on board, hoping to make him jealous, but it didn't work. Yet… he'd said he only took the best, and that he had her. She was the best? Rose Tyler, a chav from the Estates, the best?
After the day everybody lived, and Jack came to stay, she saw a slight change. He was closer to her, talked about more meaningful things. And Jack cornered her in the TARDIS one night and she told him about all her fears and wishes and Jack just grinned and promised to work his magic.
Then came Bad Wolf.
She told him that she didn't remember anything, but that wasn't true. She remembered everything, and she could feel the changes in her mind and body. He had kissed her to draw the Vortex out, and it was killing him. And suddenly he exploded with golden light and there was this new man standing there in his clothes and where was he?
When he drove away the Sycorax with a quote from Lion King, she knew it was still him. New new Doctor, she said, on New Earth. And they ran through the stars, saving worlds and people and getting stuck in jail—but trouble's really just the bits in between—and falling in love. So obvious to those around them, even the people in a parallel universe where Mickey stayed behind, yet they never saw it.
Until the beach.
She told him she loved him, and god did she mean it, finally telling him after so long of hiding it for fear that he would abandon her if he knew. The last words he said were her name, and she sobbed on that beach. She never cried again. She didn't feel a thing, the rest of the time she spent there. She was cool and distant and heartless, because her heart wasn't there with her. It was across the Void with a man who had said it was impossible to see him again.
Impossible? Hardly likely.
And then she found him again and they were together and for a while even though there were Daleks again! Everything was ok. Then the Metacrisis and that bloody beach again, and before she could tell him about the non-aging and the telepathy and everything else he was leaving her behind again. When the Metacrisis said the words, the ones she been wanting to hear for so, so long, she kissed him; couldn't help it. But then the Doctor left and she was alone with a man who might, if he was lucky enough to survive the metacrisis, give her sixty years before she was alone again.
It was only ten.
The metacrisis overwhelmed his brain, leaving a nearly-immortal Rose Tyler and her fully Time Lord (genetics are strange things, aren't they? He had said. She never told him the Bad Wolf had made their twin children Time Lords so that they wouldn't be alone) son and daughter alone in a universe where they didn't belong, with only a fledgling TARDIS as a hope of returning.
It took years, and Idris and James were teenagers, before she found her way back. She knew they were home, because when she stepped out of her TARDIS, she could feel it.
The turn of the earth.
They were falling through space, and if they let go…