Based on the song "Happier" by Marshmello and Bastille
It had been a few months since Sherlock gathered his courage to finally ask Molly Hooper to dinner. To say that he had been overjoyed since then would be an understatement. He practically walked on air. He nearly spouted off poetry. He almost smiled at people. Life had never been better for him.
"It's that Consulting Detective! The one with the hat!" whispers had always followed him, but now, they added something else as well. "Wonder if he's finally moved on from John. He seems much better these days."
Even with the John comments, he managed to be happy that so many people were happy for him and Molly.
"If there's anyone suited to being with you, it's Molly," Lestrade agreed, smirking when he caught them making out in the morgue.
Donovan had been a bit more cautious. "You better not hurt her, Freak. She deserves better than you."
(Molly hadn't been happy with her words. There had been a catfight to end all catfights right over the cadaver, where his pathologist had verbally torn the Sargent to shreds.
And if he went home and showed her his appreciation in ways that had Mrs. Hudson banging on the floor with her broom, well, that was between them and their landlady.)
John and Mary were almost as happy as Sherlock was when the detective decided to man up and do something about the woman crazy enough to love him through everything.
"She's the best thing that's ever happened to you Sherlock. Don't fuck this up," John warned.
Mary, however, disagreed. "She's happy just having you Sherlock. Don't ever doubt that."
But he was Sherlock Holmes. And if there was one thing he was good at, it was ruining his own happiness, ruining the best things that ever happened to him. And lately, he'd noticed that Molly wasn't nearly as happy as he was to be in a relationship with him.
Sure she still smiled at him, and brought him body parts, and appeared to enjoy the physical aspect of their lovemaking. She listened to his cases, and he let her tell him all about her days even though he deduced them as she walked in the door. He had never been so eager to be in the presence of someone for so long before.
But it was different now in the months since they started living together. She grew quieter, more withdrawn. She stuttered again, sometimes, even though they moved past that ages ago. Sometimes, when she sat next to him on the couch, she drifted off, clearly wanting to be anywhere else. Like the time they had gone out to dinner and run into the press before they could make it home.
"Sherlock Holmes! Who are you taking on your arm now?"
"Mr. Holmes! Is it true that your new lady is related to Janine Hawkins?"
"How long will this one last, Mr. Holmes?"
He had rushed them back to Baker Street and out of the view of the cameras. When he turned to face his Molly though, she had already cocooned into herself.
"Molly, please just ignore them. They have no idea what we've been through together."
"Yeah," she agreed with a nod, but didn't say anything else for the rest of the night.
As she slept beside him, curled against his warmth while he stared down at her, he contemplated the path he knew he had to take. It had been a difficult time deducing his own relationship but it wasn't his happiness on the line. Molly was the important part of this relationship, even if his decision would hurt worse than John's punches.
He had to leave.