Tardis, Date Unknown
As he is standing in the alcove off Rose’s bedroom on the Tardis, the Doctor knows he shouldn’t be there. He feels compelled, almost nightly, to watch her sleep. The peaceful look that overcomes her in sleep is a sharp contrast to her animated features during their time together. Her hair even, smooth along her jaw, displays none of the wild curls, charged with static electricity that she has while awake.
The Doctor has plenty of time to ponder why he needs to see this companion of his in her sleep. His Rose. Perhaps it is the calm before the storm? Her personality is never at pause during her waking hours.
Or perhaps it is the peace she has displayed across her features. A peace he can never possess; not in ten lifetimes. Not ever.
The Doctor wonders silently: how long will this peacefulness last for her? How much longer can she be his companion before it changes her forever? It probably is too late for Rose - a thought that causes the Time Lord to question his motivations often. Over many lifetimes, he has had to consider: at what cost is he to his human companions?
He doesn’t want to let go of Rose. He needs her. She keeps him conscientious. Less prone to becoming a megalomaniac, full of exacting revenge on those that would cause harm to the timeline, his friends, and her. He stuffs his hands in his pockets and rocks back, leaning on her bedroom door frame. He can almost feel the Tardis along his spine, pitying him for his sentimental reverie.
He looks at Rose, softly breathing in and out. The rhythm of the rise and fall of her chest is enough to make him want to rest. It makes him wish he could crawl in beside her; brush the hair that curls from her jaw to settle on her lips with every breath. But again, it is something he can’t let himself do. He can’t let himself love her. He can’t be for her what she needs or what she deserves: a man who will love her and her alone. He has been close to too many companions, always trying to be aloof and to disconnect him from their human emotions. He can’t be the man whom Rose can spend the rest of her life with. Grow old with.
He will never grow old or be that man for anyone.
“Oh Rose,” the Doctor says quietly while watching her, “what am I to do with you? How will I do without you?”