A/N: OH the angst. Bear with me, though.
~ Part 1 ~
Taking in a deep breath, Rose hoisted her bag onto her shoulder and walked determinedly through the console room.
Hearing Rose's footsteps, the Doctor looked up from the console screen and frowned in confusion. "Oh, are we staying at your mother's for a bit?"
Rose swallowed hard and turned to face him. "No."
His frowned deepened. "Then where are you going?"
"Doctor, I'm going home."
The Doctor smiled nervously. "What do you mean? This is your - "
"No," she interrupted. "I'm going back to Mum's. And I'm staying there."
His smiled faded. "What?"
"I can't do this anymore," she murmured, her voice cracking.
She exhaled roughly. "Doctor, you hurt me. I can't...I can't stay after what's happened."
"Wait, is this about what happened on the spaceship?"
"It's more about what happened in pre-revolutionary France, to be honest," she corrected him.
"Rose, don't be silly, that didn't – it wasn't - "
"Woah, no. No. You don't get to tell me not to be silly. I'm not being silly. I'm not a child. And in case you're forgetting, you left me – and Mickey – to chase after another woman."
"It wasn't like that! I had to sort out the clockwork robot problem, didn't I?"
"Oh, right. Yeah. Course, how silly of me to assume that we couldn't've worked that problem out together like we usually do. But then usually we're not presented with such a beautiful, accomplished lady to help, are we? So there's the difference, then. Who'd want some classless chav like me in the palace - "
"Rose, stop it. Stop it. You're not making any sense."
"Yes, I am. I am, Doctor. Because normal, decent people who are in a relationship – which, remember, we are – don't go off and shag other people whilst the other is almost getting killed by a clockwork bloody robot!"
His eyes widened in astonishment. "You don't actually think that I – Rose, of course I didn't do that. I would never do that."
"Yeah, well, you wanted to."
"No I didn't." He rolled his eyes in frustration. "Why does everything have to do with that for you humans, eh?"
"Oh, thanks. So what, then? What you had was too special with her to tarnish it with sex? So what it is between us, then, Doctor? Just a cheap little - "
"No! No, no, no. That's not at all what I meant! Stop twisting my words!"
"I'm not twisting your words. Fact is, you went and trapped yourself there with her – and that's fair enough, you had to save her, although why I couldn't come with you I don't understand - "
"Because I trust you, and you're the only one I would trust look after the TARDIS for me - "
"But you didn't think you'd be able to get back! So me and Mickey would've just been stuck there for god knows how long without any way to get home."
"I would've figured something out, I always do! Anyway, I got back alright, so where's the issue?"
"The issue is that you came back heartbroken, Doctor." Her voice cracked on the word, but she refused to let the tears spill over her eyes. She was too angry to let him see her cry over him.
"No I didn't," he replied, sounding confused.
"Not right away you didn't, but when you went back again, to get Reinette, to bring her back with you so that she could join us, and discovered that it was too late; then you came back with your letter and your sad eyes and you were devastated, don't pretend you weren't. And how do you think that makes me feel, eh? 'Cos on the one hand I want to comfort you because I hate to see you so sad, and on the other, you've gone and fallen for another woman in the space of a few hours and ruined everything we've built together over the last year and a bit."
"Rose, please listen to me. I was sad that she died, yeah, but I didn't fall for her. I let her down and she spent her last years waiting for me, which was needless and stupid and I feel guilty, that's all, I – I..."
She stared at him across the gulf of space between them and sighed sadly. "I know that you feel guilty. But Doctor, it's generally considered bad form for someone to make their girlfriend feel like nothing compared to the extraordinary other woman."
"Girlfriend? Other woman?" he spluttered.
"Yes! Okay, so it's fine if you don't want to label us as that, in silly degrading human terms, but what else do you think we are? Do you not see us as a couple? Is the sex really just sex for you?"
"No what? No we're not a couple? No we're not serious? Exclusive?"
"No, the sex isn't just sex. We are all those things, Rose. Of course we are."
"Then you admit that you betrayed me?"
He swallowed hard. "I..."
"I had to watch you act that way with someone else whilst feeling like a nagging wife for merely being confused as to why things had changed between us all of a sudden. You hurt me. Plus, you even kissed her, and who knows what else."
"I promise that there was nothing else."
"You haven't even said you're sorry."
"I am, Rose. I am sorry if I made you feel that way. It was never my intention. I just got all caught up in the events of the day and – and if I betrayed you, then I am sorry."
She stared at him for a moment, then shook her head. "If. If if if. Right then. Well. I'll be off." She nodded towards the door.
His eyes almost popped out of his head. "What?"
"I'm leaving now. Don't try to stop me. It's my choice."
He dashed over to her and grabbed her hand desperately. "You said you'd never leave me," he murmured, his voice breaking under the weight of his words.
She turned her head and steadily met his gaze as she shrugged her free shoulder. "People lie. You of all people should know that." And then she snatched her hand away from his and stepped through the TARDIS doors.
He stood absolutely still for a moment, blinking in astonishment at the empty space in front of him. Swallowing hard to stop the bile rising in his throat, his stomach churning in regret, he launched himself into action and barrelled through the doors after her.
She was already at the doors to her Mum's block, so he sprinted over to catch up. She must have heard him coming, but she refused to look behind her or acknowledge his presence. He followed her up the stairs, trying to persuade her to –
"Come back to the TARDIS, Rose. Please? Look, you just have to think about this, and at the moment you're not thinking rationally, you're just – you're reacting, and of course I deserve this but Rose, please, if you just wait, if you just stop and think, you'll see that I can make this right, I can make this up to you, please just let me make this up to you - "
"It's too late, Doctor," she snapped, turning around to face him finally, at the top of the staircase. "It's over and done with and to be honest, I'd've thought you'd be grateful."
"Grateful? Grateful!" he spluttered, suddenly so very angry. "Why in the universe would I be grateful for you leaving!"
Her jaw clenched in frustration and she seethed, "This is what you wanted. So don't you dare – don't you dare try and make it seem as though I'm the one in the wrong. This is all your fault and this is what you want. Don't pretend you suddenly give a shit about our relationship all of a sudden."
He growled in annoyance and closed the distance between them to push her away from the top of the stairs and out on the balcony, in case one of them accidentally tripped over during their row. "You're being unfair, now," he told her, voice low. "There is nothing in the entire cosmos I value as much as our relationship."
"Pfft, spare me that," she laughed, a horribly unnatural kind of chuckle that didn't suit her at all, not when he'd heard her laugh so joyously and so freely in the past.
He closed his eyes, taking in a deep breath, then exhaled it roughly. "What, exactly, do I have to do to convince you about how much you mean to me?" He opened his eyes, staring into hers fiercely.
"Nothing," she shrugged, adjusting her grip on her bag. "I shouldn't have to ask you to do anything. Goodbye, Doctor." And then she turned and stalked down the balcony.
Watching her walk away from him, the Doctor's knees gave out in utter shock. "Rose," he called out after her, gripping onto the railing to hoist himself back into a standing position. "Rose!"
She didn't turn around.