Disclaimer: Doctor Who isn't mine.
He had known he was in trouble the moment he'd felt the need to go back and ask her again. He didn't do that. If the human said no, that was it. But with Rose Tyler, that hadn't been it. He'd had to go back and ask again, to try one last time. And when she'd agreed that time, he'd been far happier than he ought to be.
But from there, things only got more complicated. He still remembered saying to her, "I could save the world but lose you." Why did she matter so damn much? He still remembered the sharp, almost debilitating grief he'd felt those times when he'd been sure he was dead, how close to being out of control that possibility had brought him to. The only worse pain he knew was that which came from the loss of his entire race, and the two weren't that far apart in strength.
It was utterly ridiculous. He was a 900-year-old Time Lord, and she was a nineteen-year-old human! It was against every rule he knew for there to be anything beyond friendship between them. But more and more he found himself wondering if maybe he could forget the rules and actually try to have something more with her.
Of course, that was out of the question now. Now that he had regenerated, he couldn't do that. He'd upset her enough by changing as abruptly as he had, and he knew that it would be wrong to pursue these feelings now. Because even if there had been some reciprocation on her part before, it was too much to hope for that she would now.
But he couldn't stop thinking about her, her eyes, her laughter, her smile... and the taste of her when he'd kissed her. It had been a dumb move; there were other ways of absorbing the Time Vortex, after all, but he'd bypassed all of those to kiss her. Why? He knew why. Just once, he had to do it.
But then it had happened again, in this body. He damned Cassandra and thanked her at the same time. He'd wanted to kiss her again, and had gotten his wish (albeit in a screwed-up fashion), but now it was even harder to get her out of his head.
This was wrong and he knew it. He should let her go, before she died or he did something he'd regret. But he couldn't. She was his forbidden fruit, and although he'd never have her, he needed her close, because having to resist the temptation to go further than he ought was nothing compared to not having her there at all.
A/N: R&R, people!