It's not until afterwards, when they are laying naked in his bed, that he realizes the full extent of what they've just done. This is also the moment that he thinks, for the first time, that maybe he can allow himself to fall in love with her.
She's a restless sleeper, and has changed positions multiple times through the night. Currently, she is more or less sleeping on top of him. Her right arm is settled next to his head and her body is sprawled across his, their legs in a tangled heap. He can feel the rise and fall of her chest as she breathes, and the feel of her breasts pushing against his chest as she inhales does delicious things to his body. Things that he refuses to act on, because no matter how like him she is, she still needs her sleep.
He can feel her hearts beating, and it's a new sensation that he never wants to let go of. He's been with many women, but none of them have had two hearts. He loves it.
He can smell her hair from where it is spread in a blonde, curly mess, across his neck and face. He wants nothing more than to have that smell burned permanently into his sense. He knows if she were awake, he would not be able to help but voices these thoughts, and she would say something very suggestive. He would blush, and she would laugh her melodic laugh.
He laughs at this. Melody Pond's melodic laugh.
Only, she's not Melody Pond. She's River Song. Before they kissed (he's not sure who initiated it) and started removing their clothing, she had explained to him why he couldn't go save young Melody Pond. Why he couldn't give Amy and Rory back the daughter they so deserved. He had fought. He had told her he could give her a childhood filled with more than just cages and training and hatred.
But now he knew.
He knew that if he saved her, if he saved poor, scared little Melody, none of this would happen. The nights spent fiddling with Sexy and trying to figure out who she was. The Byzantium. The Library. All of the flirting. The kiss at Stormcage.
He agrees not to go for two reasons. One being the fact that, at the time, she had been wearing a nightdress that was very, very short, and not at all appropriate for their conversation (he can tell she's Amy's daughter just by looking at how short it is). The other being that he remembers a promise he made to a future her, back when he wore long coats and was Scottish. He was handcuffed and she was about to kill herself to save everyone. He remembers it so, so clearly. He doesn't want to remember it.
As they lay there, he wonders if that's how she first met him. When he died. He knows she was trained to kill him. He knows she was in Stormcage because she killed someone. A man. A good man. Was he the good man?
How perfect would it be, he thinks, if he IS the man she kills. It's quite possibly his fault that she died. He should have been the one to sacrifice himself. Not her. It's the romantic's dream come true. Two soul mates who are not only backwards, but also killed each other. It's too good to be true.
But as he looks down at her sleeping form, he stops thinking these thoughts. She wouldn't like it. He knows, in their tragic situation, all he can do is appreciate the times when they know and love each other equally. He knows she knows much more about him than he does her, but he thinks the fact that he is willing to learn is enough. The fact that he wants nothing more than to just remain with her in the TARDIS forever, and not care about anything but them.
She stirs, and he thinks for a moment she has woken up. She is just shifting. But he hears something, so soft the has to lean down a bit to catch it. "I love you."
She is talking in her sleep, and he smiles. "I love you too, River Song." And he does. He really, truly does.
I don't own these characters or anything mentioned that sounds vaguely familiar. Thank you.