AN— I got thinking about how difficult it must have been for the human Doctor in Pete's World; he left everything he ever knew behind, his entire history, to go to a place where Time Lords had never existed. Whatever chance the regular Doctor had of finding other Time Lords again, he had none. And he had to contend with some of the more difficult aspects of humanity, his memory not being as good, and the emotional rollercoaster we all navigate every day. Humans have evolved to read one another's faces to sense when we're in danger, but mostly we use it to try to read people's thoughts in a very primitive way that is often wrong. We also tend to engage in negative self-talk, which has a rough effect on us, but on someone new to the human game it must be just frightening.

Anyway, that's a lot of babbling.

Part Human

He needed to sleep these days, not that he ever did. Instead he lay in the dark looking blankly at the ceiling, or sat on a kitchen chair staring out the window (or at the window, or somewhere in the middle), or stood in the garden with a slowly cooling cup of undrunk tea in hand. His body demanded sleep, but his mind wouldn't allow it. Maybe that was it—that his mind and body hadn't synched yet. Or maybe it was that other thing he was trying to avoid thinking about.

Disgusting. That was how he had described the single-hearted state of humanity he had found himself in to Donna. It was disgusting, and overwhelming and terrifying, the way emotions just crashed in and out of his body as though they were the ones in control. They couldn't even decide whether he should be happy or sad, or the myriad of states in between (some of which he didn't even know a name for).

Now though, he figured that it might have just been a period of bedding in, because his emotions weren't so wild anymore, in fact they barely troubled him at all. He went from feeling absolutely everything to feeling next to nothing at all. He didn't know which was worse.

He was aware of the way Rose looked at him, it didn't matter what he or the other him had said, she still didn't believe they were the same man. Well, she had always been perceptive. He understood that better now too; he could see things in her expressions that he couldn't have before he became part human. He could read her now without her saying a word; he knew what she was thinking all the time and it made it harder to ignore the painful things she thought. Like how he'd never be good enough, or how she felt duped into taking him on and now he was a burden to her.

She sat down next to him at the table, placed her hand on his and he flinched. It was involuntary, mostly. He didn't want her pity. She leaned in to catch his eye. "Why don't we go out for a walk today? It's lovely outside, you don't even need to get dressed, just put on a pair of shoes…"

His face aped a smile and she looked away. "Maybe later," he said, as he always did.

"Okay," she said and left him alone again. He must have been such a crushing disappointment to her. He cringed thinking of the idiot he'd made of himself the first time they were together, the only time.

They were kissing on the beach when his other self slipped away. The sound of the TARDIS dematerialising caught Rose's attention, she was annoyed. He tried not to watch as it faded away, but he couldn't help it. It was gone. Gone forever. Seven hundred odd years he'd spent in her warm embrace, and all that was left was the flicker of blue on his retinas, until he blinked and that was gone too.

And not only the TARDIS, but the other him too. He had been so lonely being the last for so long, and then they became three (soon to be two, he hoped his other self would be gentle with Donna, but knew he wouldn't—at least the other him could do it, he wouldn't have been able to anymore). Now they were separated and it felt like his absent second heart had been clawed out of his chest.

His knees weakened as emotion surged through him and he was sobbing, properly sobbing like never before, in front of Rose and Jackie. Rose held him until he somehow managed to pull himself together enough to be able to leave for the hotel that Pete had booked them into. On the way Rose distracted him by telling him about all the brilliant things she had been doing in his absence; she really didn't need him at all.

He made love to her that evening and it was, frankly, shocking. The uncontrollable need and the horrific swing of desire through his body; how did humans deal with this? How did they avoid destroying one another all the time if this was what they had to contend with?

Gratefully Rose was more than willing, otherwise, he daren't think. And when he came it felt like dying, like being shattered into a thousand pieces and being happy about it. What followed was yet another crash of emotion and he wept again, still inside her, sobbing like a lunatic. What must she have thought? She just hushed him and stroked his back.

The next day they returned to the Tyler estate in silence, with Rose cradling his hand in hers. That was almost four months ago now.

He sat on the expansive sofa, the television was on and the colours danced across his unfocused vision. He was aware of a ghost in his peripheral vision, he knew it was a symptom of insomnia; he'd read that somewhere at some point. He didn't know why his mind wanted it to be her—to be Susan when she was a child. She played peacefully on the carpet in the corner of his eye, not making a sound, and he didn't dare look directly at her and spoil the illusion. Susan had never existed in this universe, nor had any of the others, nor their home.

"Mind if I change to the soaps?"

He blinked and turned his head to see Jackie.

"I'll take it you don't then?" she said, sitting down next to him and changing over. He wanted to turn back to Susan, but Jackie kept talking, explaining to him what was going on in Eastenders in this universe, rabbiting on and on about inane characters and ridiculous plots. "Jackie!"

"Finally! That's the first thing I've got out of you in two weeks. It's been like living with Marcel flaming Marceau."

The Doctor blinked at her. "Sorry. I should help around the house more."

"Don't be daft, we've got maids for that." She switched the television off and rearranged herself to be turned more towards him. "We're all worried about you, you know. Not just Rose, me and Pete too."

"No need, I'm fine."

"Do you think if you keep telling yourself that, that it will magically be true? Because it won't. I remember when my Pete died; I never thought I'd be able to get dressed again. Stayed in my nightie for weeks, so I did. Shipped Rose off to mates who were only too happy to help out for the first while. But in the end the offers stopped coming and I had this little girl to look after on my own. What could I do?"

"She made you feel better, though?"

"Not even a tiny bit; she just reminded me of Pete. Of course I loved her, of course I did, but for a long time I was only going through the motions. Get up, get dressed, get Rose sorted and fed. Just getting through the day until she went to sleep again, and I could go and take Pete's favourite t-shirt out of the drawer and hold it up to my face—breathe him in for a bit, pretend like he wasn't gone for a couple of minutes."

The Doctor looked at Jackie; the tears brimmed on her lashes and she unashamedly blinked to send them spilling down over her cheeks. He felt hot streaks run down his own and realised he was doing the same.

"The other one, the other Doctor, he would never have sat here listening to me witter on or have had a good old cry with me. You're different to him; you care what people think. A bit too much probably, but you're only learning yet, so I'll let you away with it."

The Doctor laughed, actually laughed, the first time since he came to this universe. "It's not easy this, this human thing. I keep forgetting things. I'm worried that I'll start to forget important things, like people."

"A night's sleep will sort that out. I can barely remember my own name when I'm tired, and you haven't slept in weeks."

"Months, actually." Jackie was smiling at him and it wasn't pity he read, it was compassion. "I find myself thinking about my granddaughter, Susan, a lot."

"Sometimes I forget how long you've been knocking about. Rose mentioned you were a dad, but she didn't say anything about grandchildren."

"I never told her." He felt his cheeks flush with shame. "I really should have told her."

"Not everything is Rose's business, she knows that."

"Jackie, why are you being so nice to me?"

"I'll have you know I've always been nice."

"I'm sorry."

"And stop apologising, it's driving me absolutely barmy. Just take it that you're already forgiven unless I say otherwise, okay?"

The Doctor smiled at her. "Can I tell you about Susan? I'd really like to talk about her."

"Of course you can, I'd love to hear about her."

He told her all about Susan and didn't stop there; he told her about his TARDIS and how he missed it terribly, and how he often thought about the other him and what he might be doing. He told her about all of his companions before Rose and at some point he found himself lying with his head on a cushion in her lap, telling her about what it meant to him to meet Rose when he had. Jackie just let him talk and stroked his hair as though he were a child again.

He didn't remember exactly when he had fallen asleep, but he was vaguely aware of Rose entering the room and Jackie quietly saying, "Leave him rest for a while," and Rose kissing him softly on the temple.

There was one human emotion that never became frightening, regardless of how intensely it burned, and he was blessed with an abundance of it. He always had been.