He didn't do domestic.
Domestic was grocery shopping and matching his-and-hers towels and sitting down to watch a favorite programme on the telly every evening. Domestic was folded socks and holidays with the in-laws. Domestic was exactly the opposite of how he wanted to live. He had countless more centuries of life and all of time and space at his fingertips.
And yet…
The Doctor stopped pacing around his room and dropped into the armchair nearest to him. He absentmindedly picked up a small clockwork gizmo from the coffee table and turned it over in his hands.
Seeing Rose holding her infant self today had done something to him. Of course, it had created a paradox that had meant he had temporarily ceased to exist. But then Pete had sacrificed himself, fixed the time line and restored the Doctor to existence. And the sight of Rose holding an infant had been plaguing him ever since. Only it wasn't herself as a baby. It was her baby. A child that she would one day have.
The Doctor closed his eyes and let himself see down that time line. The images made his hearts beat frantically at the vision of a life she could have. Rose in a white gown, smiling from behind a veil. Rose standing in front of a cot, her hands resting on her swollen stomach. Rose sitting in a rocking chair, cradling that phantom infant with dark hair. Rose laughing as she chased playfully after a little girl with dark curls; a little girl still unsteady on her chubby toddler legs. She turned to face her mother and the Doctor braced himself to see some unknown human father reflected in that face. Maybe it was even Ricky the Idiot.
The child was Rose in miniature. The same wide mouth, the same upturned nose. But the eyes, those icy crystalline blue eyes, were his.
The Doctor heard the child giggle, and saw himself appear to grab her and swing her high in the air so that she shrieked with glee. He swept her into a tight hug, and then Rose was there, holding his arm, smiling up at him and their daughter, a second child on the way.
A strangled sob came out of the Doctor's mouth as he opened his eyes and returned to the present reality. The bit of clockwork gadgetry fell to the floor, unheeded. No. That couldn't be a possibility. It had to have been a dream, a fantasy. He must have strayed from a timeline into a daydream. The was not something he was allowed to have, or to even want. Surely Rose would prefer a different life.
As the pounding in his hearts returned to a normal rhythm, the Doctor locked away those effigies. He wouldn't be looking at them again.
Even though he wanted it, he didn't do domestic.