Martha had been the only one to ask. On their way to their bedrooms, each companion passed the Doctor's room (which he was rarely in) and a white door adorned with a red rose. When Martha tried to open it, it was locked.
Donna didn't need to ask. She already suspected.
Amy found him inside once, sitting on the bed, staring into space and breathing in the air, but she didn't ask him either. It looked too sacred to mention, but she couldn't help but tell Rory.
"What do you think?"
He just shrugged, but he figured it had to do with a woman. Things like that always did.
It was his last trace of her, and the day the bedrooms fell off the ship, he felt like he'd lost her all over again. He slumped against the console as Rory and Amy went to find their new room and he knew that was it. No more Union Jacks and leather jackets and Victorian dresses in the closet. No more pictures on the dresser of her with his old selves. No more posters on the wall from events they'd gone through time and space to get to. No more smell of…
He pushed himself up, following his nose down the hall. Then he saw it, across from his door just as it had been for years.
A white door with a red rose.
The knob turned easily, and then he just had to nudge the door with its fingertips for it to swing slowly until it hit the wall. He leaned against the doorframe, arms crossed, and smiled sadly. The purple comforter looked thick and soft. On the opposite wall were the Elvis, Beatles, and Broadway posters hanging among pictures of her in famous places with famous people. The frames were back on the dresser, pictures of him and her from her birthday, Christmas, and one unnamed special occasion where Jack was on her other side even as she leaned closer to the Doctor. A long black gown hung on the closet's open door and he could just make out his old leather jacket and a couple of her old clothes (a denim jacket, a pink dress, skirt overalls…) inside.
And stronger than it had been in a long time, roses and tea and chips, the one smell that just screamed Rose Tyler, permeated everything.
He leaned forward, holding on to the door frame with one hand and reaching for the knob with the other.
"Thanks Sexy," he whispered as he pulled the door closed.
The only answer was an affectionate hum. The Doctor crossed the hall into his room and cried.