Thanks to MLC! First for reading this last night, I would have trashed it if she hadn't, second for betaing it for me this morning.
This is AU from the series in that John was not there to see a scan done on the baby as mentioned in S3E3.
The door to 221B Baker Street closed. Seconds later, John came into view, gave a tired smile to his friend and went into the kitchen.
"Tea?" he called out.
From his chair, Sherlock hummed, lost in thought.
John's marriage had ended. Separated from Mary for months and then busy helping Sherlock disprove Moriarty's return, he had not lived intimately with his wife long enough to realize the pregnancy, like everything else about the former assassin, was fake.
Their final conversation had been full of hurtful words.
"You didn't check to see how my pregnancy was going while we were apart! You didn't ask about doctors' visits or how things were progressing! Were you even concerned about your child?"
"Of course I was, but there was no baby to be concerned about! It was just another lie! Like the woman I married, it never existed!"
"If Mary Morstan had existed and died in childbirth, you would never have mourned for her as you did for Sherlock Holmes."
Both admitted there was nothing to salvage and that night John had showed up at Baker Street with a bag of clothes.
Without a word, Sherlock had read everything on his face, given his friend an unexpected hug and played his violin while John put his few belongings away. Now, for a third time, they were sharing a living space and Sherlock couldn't help the warm feeling in his chest. Even during difficult times, he felt content when John was near.
He then remembered something his mother had once told him. "Home is where the heart is. Your father and I could live in a castle or a cottage and I would be content with my lot in life because he has my heart and is my true home."
Sherlock felt his own heart begin to race.
Before John, Sherlock had used drugs to fill the emptiness inside and calm his frantic mind. After John's arrival, they were unnecessary. During his two-year absence, he had relapsed more than once, always careful to wait until he was moderately safe. He had managed to fight off the need while helping plan the Watsons' wedding but given in afterward. He had only stopped again because of John. John, who had found him in a drug den, forced him to be tested and chose to stay with him as Sherlock suffered from withdrawals and healed from the bullet wound Mary had given him. While in custody after Christmas, it had not been possible and John had been by his side as he proved James Moriarty was not returning. Then the Watsons had separated and the two men were together at Baker Street once more.
Sherlock rested a shaking hand over his chest. He finally understood his mother's words and it terrified him.