It hurts, most days. Sometimes she'll get really involved in a case of some sort and it'll go away – not entirely, it's still there, an ache in her chest – but she'll forget to think about it for a while.
And then it comes back. The expression on his face when she saw him last, the way he opened his mouth and then disappeared. Gone – and she'll never know what he would have said.
Sometimes, at lunch, when she's sitting alone and not thinking about anything, it comes on strong as the day he said goodbye forever, the day he burnt up a sun to talk to her. Then she has to go to the bathroom and have a cry.
Her coworkers think she's got someone at home – a relative with a terminal illness, or some such thing. She doesn't tell them – how could they understand?
She has a few flings, nothing too serious. She can't get him off her mind, and she always breaks it off before it goes anywhere. How could anything compare to what she had with him? It was so much more than romantic love, so much more than desire, so much more than friendship. It was a love and a unity that transcended all of those, that can hardly be put into words.
He was never perfect, and she certainly wasn't, but they belonged together, and when they weren't anymore, it hurt.
She tries to always do what he would have done. She works for the good of the earth, for humanity. She sees numerous alien arrivals and helps Torchwood to foil them. But it's always there, that pain. It chokes her and makes a permanent home for itself in the pit of her stomach. Sometimes she just goes home and sits down and stares at the wall for hours, because it hurts too much to try and do anything.
She misses him, but it's more than that. It's the knowledge that she will never ever see him again, and the memory of her time with him like a taunt in the back of her mind.
And she can't even think that without the pain rising to choke her, because didn't he once tell her never to say "never ever?" And that memory is painful, too, for its content.
And try as she might, she can't stop her heart missing a beat every time she sees someone in a trench coat, or turns a likely corner, or sees a phone box, though not the right color or shape, because what if? What if?
Rose Tyler misses the Doctor, and she doesn't think it will ever stop.