A/N: So I realized this might be slightly out of order. John doesn't know about Mary's betrayal during their wedding, so this is the updated version of this chapter. :)

"I do." John's voice was as steady as his hand when he held a gun as he bonded himself to Mary. Sherlock didn't turn away; he couldn't. He wouldn't do that to John Watson, not even as he stood there and the heart he never knew he had was slowly cracking, shattering as John chose someone else.

"I do." Mary's voice was full of emotion. Disbelief that she'd ever make it this far; elation that this was happening, and something deeper that Sherlock couldn't quite deduce. But that was John, Sherlock thought. He chose Mary over him. And Sherlock didn't turn away; he couldn't. He wouldn't do that to John Watson, not even as he stood there and the vows played in his mind, except it was his baritone voice ringing out across the crowd and his sharp black suit standing there.

Sherlock buried these memories in his mind palace as far down as they would go and locked the door as he walked towards the main street. The sound of cars grew ever closer as he stepped onto the sidewalk of the main street.

His arm almost raised to hail a cab, but before he could do so a plain black car drove up to the curb directly next to Sherlock. He didn't berate Mycroft's dramatic flair as he got in the car, but instead numbly sat there staring out the window.

Widowed, thirties-thirty-six? No, thirty-four?-and with two daughters-

Single, forty-five?, owns a flat, never been in a relationship-

Sherlock tried to distract his mind by deducing random strangers whenever they stopped, but he couldn't keep his mind off of John.

"Dance," Sherlock said. He didn't want John's wedding to be ruined in even the slightest way; people would give them strange looks if they didn't dance.

"Mm?" John was slightly distracted. Sherlock elaborated.

"Both of you, now, go dance. We can't just stand here. People will wonder what we're talking about."

John snapped back to the present. "Right."

Sherlock felt Mary touch his arm. "And what about you?"

"Well, we can't all three dance. There are limits," John chimed in.

"Yes, there are," Sherlock agreed, though he didn't agree at all. He didn't want Mary there; he wanted John to himself, and he knew that was what John would call selfish of him to say, but it was true. There had been a growing pain in his chest all day, and eventually he had come to realize that it was because he was watching the man he loved choose someone else.

Sherlock realized suddenly that they had arrived at Baker Street. He snapped back to the present and opened the door. In a rare show of humanity, he nodded at the driver in thanks and turned to walk up the stairs to 221B.

He opened the door and went upstairs, fighting back tears-sentiment! Sherlock nearly stumbled into the flat, his usual grace out the window as he felt the past day come crashing down upon him in a sudden avalanche of stabbing pain in his heart. He shed his coat and scarf, leaving them in a heap on the floor, and flicked the lights on. He glanced up and saw Mycroft sitting in John's armchair-John's armchair-before he stood up and took a few steps toward him. Sherlock stood there numbly, feeling oddly bare.

"Oh, Sherlock," came Mycroft's soft voice, as he took a step forward and began to embrace Sherlock. Instead of telling Mycroft to piss off, as he normally would have, he sank into the warmth of his brother.

"I do"-

"Come on, husband"-

"The signs of three"-

"Mary Watson"-

And Sherlock felt the locked door of his mind palace burst open. He cried, devolving into broken sobs as he stood there, Mycroft's arms around him. He could feel that Mycroft didn't truly understand the hurt that went along with what he was experiencing, but Mycroft had never been the emotional one, it was always Sherlock.

Always Sherlock who felt pain, hurt. Love.

Heartbreak.