A/N: Not sure if this is going to be two or three chapters, but this first part is set directly after the Doctor leaves Demon's Run in AGMGTW.
He grinned like an idiot as he ran to the console, flipping levers with wild abandon as he sent his girl into the time vortex. It was too good to be true, much, much too good, and he needed to be alone for a moment to properly process.
River. Oh, River, beautiful River, maddening and amazing and wonderful River, was Melody Pond. Which meant she was human plus Time Lord, and the implications of that...he giggled aloud, twirling himself around the control room, happier than he had been in a long, long time. Of course, there was the slightly inconvenient fact that as a baby she had been stolen away from her parents, and Amy and Rory would probably never really forgive him for that, but all of that guilt could wait, because right now, RIGHT NOW, he was over the moon.
She wasn't just part Time Lord, she was human plus Time Lord. And he loved humans, loved them more than any species he'd ever come across, partly because in some ways, they reminded him most of his own people. But he would never get too attached, never get romantically involved, because he just couldn't. He could love them, yes; he loved all of them, really. A few of them he even love-loved. He had loved Rose, and he couldn't deny it any more than he could have stayed with her. Being in a real relationship with a Time Lord was more complicated than any of them could have ever understood; it would eventually drive any human mad. What happened to Donna would have happened to all of them if he had let things go too far. Not to mention the fact that any relationship he could have would be short-lived, from his perspective; human lives were short, and deep down, when it came to romance, he selfishly guarded his heart. So he kept his distance as best he could.
And now there was River, and he'd seen the DNA for himself. She could live for years, possibly centuries, with him. She could handle him. What's more, from everything he'd seen of her, she WOULD handle him. He wouldn't be alone.
Grinning like an idiot, he let out a loud whoop and set the TARDIS on a path to Stormcage, punching in the first date and time that came to his mind; just after he had dropped her off from Florida. Just after she had kissed him for his very first time.