He comes to her at night.
Clint slips silently into her room, knowing exactly how quiet he must be in order to avoid waking her. He holds his breath tight within his chest and breathes through parted lips. He wears socks so that his feet don’t stick to the slick floors, through sometimes he gathers static electricity within the hairs on his arm just walking across the carpet near her bed.
He stands by the door, first, examines her slim silhouette on top of the sheets (which she never sleeps underneath, in case they slow her down). There are no windows in her room, so she is outlined by the dim blue light from the laptop by the wall. At this distance, he feels comfortable; if needed he can dart back out the door, slip down the hall and away, and she would never know he was here. But he can’t see her breathe from here, so he creeps closer.
Next he crouches by the bed, just two feet away. He can see her breathe, watch the dark material of her suit rise and fall with her ribs. He can see her better, too. He sees the red glint of her hair; he sees how the curls have tangled under her cheek and how they’ve frizzed and knotted. He knows she will look perfect in the morning, beautiful and calm and utterly put together, but for now she is undone. He only ever sees her like this at night.
Sometimes, when he’s feeling brave, when he forgets to worry about what she’ll think if he wakes, he moves even closer. Sometimes he leans over the mattress (very careful not to touch it even the slightest, since that would wake her, he’s sure) until he’s close enough to hear the soft rasp of her breath. Sometimes he reaches out and moves his hand through the air over her curves, imagining the sensation of her skin. All he knows is the rough touch of her callused fingers on his and the shock of her blows, so his imagination never satisfies.
He is always tempted to smell her hair (he toys with the thought that it would smell of Garnier), but he never does.
It’s only fair, he rationalizes. She has saved his life so many times, watched over him while he slept, and kept his unconscious body safe; he feels compelled, at times, to watch over her. He knows she feels nothing more for him than a debt. The weight of her gaze frightens him away, to be honest. It forces him to confront the fact that they will never, ever be more than comrades.
On some nights he sleeps in his own bed and wakes when the night is darkest, cold and alone, sheets tangled around his legs. On those nights, he walks across his room and pauses by the door, runs his hand through the short bristles of his hair, and calls himself a fool. He goes back to the bed, pulls the sheets around himself, and forces himself to sleep. In the morning, he calls himself reasonable and meets Natasha’s gaze steadily.
But that is only some nights.