I've got the scars from tomorrow – katana_fleet – my songs know what you did in the dark (light 'em up) – fall out boy
He senses her mind before she and her crew burst through the door in the Library. A mind, open and searching, definitely female, smart, very brilliant, with tinges of something that could be love around the edges. He tries to repel the searching mind with its love, that love that he's feared since he lost his Rose Tyler, tries to push it away, but can't. He sees her face through the helmet and he knows it's her mind with the first terrifying words of "Hello, sweetie."
He knows that it's love around the edges—love is dominating her whole mind, in fact—when she quizzes him about diaries. Her face falls as she realizes he's not joking, he doesn't know who she is, and according to her he should but he hasn't met her yet—how it that even possible?
He wishes for just a moment that he did know her.
Gorgeous woman, mind open as a Time Lord's can be, if he wants it—he's kept his own nailed like a moldy coffin eight feet under since the Time War, but this woman, this human, can worm her way through the cracks and start melting that shard of ice that's pierced his heart since he destroyed his own people. Not even Rose or Donna could get past that block but this Professor River Song has (so okay she is amazing but still)—
She knows his name. How can she know his name? There's only one reason he would ever tell anyone his name, only one time he could, but… spoilers.
When she whispers his name, she says it with such love, pure love that he knows; he knows then who she will be. And he hates it. Because now he has to meet her again, can't rewrite time and save everyone, least of all her.
She dies for him in the Library. As she speaks her final words—It's okay, it's not over for you. You'll see me again. You've got all of that to come—he only wants to save her, because just once, just this once, everyone should live. But only once in a million days can that happen. But the stars may yet go dark one day if he ever accepts that he cannot save everyone.
He saves her mind to the database because he couldn't just let her fade—her mind deserves to live on—that wonderful, open mind full of love and compassion and something nearly like his own mind—young and old and vivacious but just so tired.
With the new regeneration comes new words—Yowzah, never mind, never using that word again, fine—and new foods—fish fingers and custard, not beans or bacon or apples or, Rassilon forbid, yogurt—and a heart still torn and broken from the loss of his Rose Tyler and his friends—but it's mending. Of course, his overwhelming love for Rose has faded—natural, with the new mindset, brain, and heart, it always happens like that—but he's got to find someone and this tiny—okay, not so tiny—she's all grown up now—Scottish Amelia seems good and so he takes her off to see the stars.
Everywhere and anywhere, every star that ever was—but with all the distractions he does not forget River Song. His archaeologist-maybe-friend-maybe-wife person with the mind of love and time. Who's already dead and saved to the biggest Library in the universe.
He meets her again, catches her falling from the falling Byzantium. Her mind is more wary, just a bit—she's only Doctor Song, it turns out, he's got so much time to come, is that good or bad, he's thinking fantastic—and his own mind—opening just a tiny bit—tries to wrap around hers, tasting it, sensing the love still pouring from it.
She loves him. Loves him that much that she would die for him, did die for him, a man who didn't know who she was.
He knows now, knows who she'll probably be.
It's only confirmed in Amy's backyard, the night he reset the universe with Big Bang the Second. Are you married, River? Are you asking? Yes. Yes. (Hang on, wait, stop, did she mean yes, or yes?) He tries to pull away from her, but can't resist the pull and mystery of Professor and/or Doctor River Song. Probably his future and past and present wife. She's Mrs. Doctor from the future, isn't she?
He tries to push her away. Trust her? Seriously? No. He can't, she killed a man, a very good man, the best man she had ever known. And she's not telling him. But he does trust her, obviously trusts her, she knows his name, for heaven's sake, he has to trust her, he will trust her, he did trust her—but she won't tell him anything.
River… Who are you?
And it's only the infernal "You're going to find out very soon now. And I'm sorry. But that's when everything changes" and he just wants to throw her out of his TARDIS—which does not need the stabilizers, thank you, River, honey—or kiss her—where does one put the hands when a woman kisses you—or just watch her and guard her and never take her to Darillium and its Singing Towers or let her go to the Library.
And her mind still sends love towards him sealed in a nice blue envelope, but it's more cautious because she knows that he doesn't know her quite yet and she doesn't want him to leave her. But he's toppling toward the edge of the never-ending abyss of LOVE.
She's Melody Pond. The woman who loves him and died for him and very likely has married him and is the daughter of his two best friends and—oh goodness, they're still watching—look away, Ponds—go away, Ponds.
He runs away, leaves them for River to sort out, because he thinks he's going to laugh or cry or dance or all at once. Probably all at once.
He runs off and finds another River, slightly older, who knows what he did and almost did at Demons Run, and does all three. He takes her to a ball in nineteenth century Earth and they run from the rogue Dalek—what is a Dalek doing in the middle of Saudi Arabia, anyway—later he finds that there's a whole colony there, in 1876—and she kills it with a brisk coldness and flair that he shouldn't like but he kinda does, really (loves it).
Back on the TARDIS he kisses her and opens his mind to her, leaving the Library in a dark and secluded corner that she obviously knows well, for she never pushes her mind toward it.
But she's got the same barriers.
She doesn't tell him that she's the infamous Mels of Amy and Rory's Leadworth—or that she was trained to kill him, his own bespoke psychopath—or that she knew the Silence or at least of them—or that she's now successfully killed him twice, if he counts the pyramid.
The pyramid. The marriage across all of time and space.
Of course, he really doesn't say his name—she needs to know that he's inside the Teselecta so that she'll kill him—somehow that would sound wrong if they were anyone other than the Doctor and River Song—and anyway saying his name seems to send her one step closer to the Library. And he can't do that yet, he's only just beginning, she's only just beginning.
Love. The most powerful thing in the universe. Love resets time and melts this heart with a sliver of ice inside and lets the psychopath save the man she was trained to destroy and allows River Song to spend her days in prison—but her nights with her husband.
Every date night they become closer, closer, closer, closer—less and less boundaries of the Time Lord minds, until finally that day where they both have just one or two black barriers.
His is the Library. It always will be.
Until the night he takes her to Darillium, to see the Singing Towers—she had begged him and begged him and she was a professor and she had won his name from him—amazing what a good snogging session can lead one's wife to promise in exchange for a name—River promised to not shoot his fez or another hat again—well worth it. An even trade, he thought, but knew it really wasn't, no hat, no matter how cool, was worth losing River Song. His wife. But the next night was Darillium.
He shows up on her doorstep, with a new haircut and suit. He takes her to Darillium, to see the Singing Towers—and he cries—tries to hide it, but he can't hide anything from her. He gives her his screwdriver as a clue she will understand too late.
He knows it's time. Her time. Time to go to the Library.
But he kisses her with everything in him—every broken crack in his old, old heart—and sends her off with her believing that they'd see each other again, soon, they'd have so much more to come—but he knows.
He sees her again afterward.
Manhattan.
But something's just a bit broken in him. She's his wife, he loves her with every particle of his regenerative being, but she still hides things, pain—a broken wrist that he caused—never let him see the damage, ridiculous—he needs to see—from him, why because there are no more spoilers that he could possibly hear.
To him, she's a ghost, really; she's always been a ghost—ever since the Library, so, so very long ago.
Hundreds of years has she been a ghost to him, flitting in and out through his life. This River in Manhattan is just recently a professor. He breathes a silent good luck wish to his younger self. But he tries to love River more than ever, tries to keep her close to him for a while longer.
After Amy and Rory are taken they let their minds completely free in the TARDIS. She senses that he's already seen her ending, so she lets everything go. He leaves the one barrier up and lets the rest go, and as he stares at her, tears in both of their eyes, he sees her pain shining in the green eyes he could spend a thousand years gazing into.
The pain she's tried to hide for the decades of their marriage—mostly she succeeded but now she's letting the barriers down—he reaches for her and lets her cry. As he kisses her his love pours into her mind and he forces her to see that she doesn't need to hide. Ever. Not even when he doesn't know her.
And now she's ready for the Library. No pain will be hidden from him—he'll see the pain of spoilers—she knows his name—and his previous self will know exactly what this him has already been through. Love. Pain. Loss. But such joy. Joy without compare.
River Song. Melody Pond. The woman who murdered and married him.
His precious love and his equal.
The lost Lords of Time tossed in the sea of time and space.
He'll know, there in the Library.
The last time he sees her is in his dying TARDIS. She has opened her mind to him once more, searching, loving, hoping—when he pretends to not notice her she deflates just slightly, but soldiers on, the strong and brave and caring River Song, Melody Pond as always.
Finally Clara has jumped into his time stream and she turns to slap him but he grabs her arm because this is the last time he'll ever see River Song and he has to say something to her—and anyway she needs to realize that he can see her and has seen her and loves seeing her and does not ever want to stop seeing her.
Everything ends. But not love. Not always.
His mind is, for the first time, completely and without any hesitance open to his wife—his River—because she knows.
Knows about the Library and that last dark hidden space in his heart and mind—that dark space that has always been there for her—is gone, gone forever—and she breathes in the love, love, love he has for her.
She is always there to him. And he always listens. And he can always see her. But the pain.
He thought it was going to be too much and it is so he pulls her to him and it's safe to say that he's the only man who's kissed his wife who happens to be a beautiful, invisible ghost in front of his time stream and three disturbed friends inside the decaying remains of his beloved time machine.
Finally, finally he lets her fade.
"Hello, sweetie" were her first words to him.
It's morbidly fitting that "Goodbye, sweetie" be her last.
But as he jumps to rescue his little impossible girl who is now not-so-impossible, his mind and heart are breaking, shattering into impossible and uncountable shards, wondering how—how—how—will he survive without the love of his River Song always there for him and her mind always open and love pouring from it and his wife just waiting for him, the lonely Time Lord.
The last of the mad Time Lords with his two broken hearts.