Life certainly wasn't easy after that. It wasn't anything like before Sherlock's heart had been attacked, but it was certainly better than the period between hearts.

But Sherlock was on a cocktail of drugs, and his immune system was permanently in hibernation, meaning that he couldn't just ignore a sore throat or a cough, because odds were he'd end up in hospital without early intervention. John also made a strict 'no dive tackling criminals' rule, which Sherlock insisted he didn't do. John returned with video footage that proved otherwise, and Sherlock reluctantly agreed. And there were things they both hated, like when John got the flu and Sherlock had to go live with Mycroft for nearly a week. And it really wasn't easy. But it was far better than the alternative.

It was always in the back of their minds, what Sherlock had said that night at the pool.

And of course it wasn't true. Sherlock indeed had a heart. A heart that could break, and hurt, and even fail. So John was going to ensure that no one could ever tell Sherlock he didn't have a heart, even if he had to show them the scar that was just beginning to fade on Sherlock's chest. (John had also sworn that if he ever met the person who'd 'reliably informed' Sherlock of that, he would make sure they realized just how wrong they were.)

And John was determined that new heart would remain in Sherlock for a very, very long time. The anti-rejection meds had to be taken on a specific schedule, and John knew that Sherlock wouldn't have been able to do it if he were alone. But he knew that Sherlock liked being able to say that John was the only reason he still had a heart.