A/N: I know this is late, but I was going to post this for Valentine's Day. It's a 221B that I wrote a little while ago but never posted. Hope you enjoy!
Molly had known all along, she supposed. The moment she saw Sherlock with John she could see the connection. Anyone could see it in the way they walked so close together it seemed only logical they should hold hands, or the way they almost finished each other's sentences in conversation.
She should have been upset she supposed, or at least put out. He was, after all, her Sherlock, the man she had pined after for what felt like years. But strangely, she wasn't. If anything she thought it adorable how neither could see what was staring them in the face. Every time they stared at each other longer than flatmates (or, dare she say, friends) should, every time Sherlock smiled, really smiled, at John, and every time they "accidentally" brushed against each other, Molly had to suppress a grin.
She didn't bother now. There was no way they would notice after all.
They certainly hadn't noticed when Molly came in and found them wrapped up in each other, John gently pressing Sherlock against the wall of the lab. Hands cupping the taller man's face, the doctor seemed to be kissing Sherlock with everything he had. With his arms locked around John's waist, Sherlock passionately returned the kiss, emitting soft moans and whimpers every so often.
Molly quietly slipped out, positively beaming.
A/N: I hope you enjoyed this! Constructive criticism is encouraged!