It wasn’t Sirius’ fault, exactly.
Duel’s go wrong all the time, and DADA is the place for it.
Which is why nobody batted an eye when a spell went wrong, firing out of Sirius’ wand faster than ever before, straight into Peter. He was a little too shocked to block it, instead letting his face pale as he fell.
“Shit, Pete!” Sirius crouched next to Peter, the others coming over quickly, including the professor.
“It’s okay, quick fix.” He muttered something, his wand pointed at Peter, who woke up immediately. “Alright there, Mr Pettigrew?”
“Hm? Yeah, I’m fine.” He stood up and grinned at Sirius. “No worries! I didn’t block in time.” Remus glanced at Sirius, who had gone unusually silent.
“You okay?” He asked quietly, and Sirius turned to him, forcing a grin onto his face.
“Yeah, I’m fine!” He said with overcompensating enthusiasm. Remus frowned, but dropped it.
He didn’t know what was going on until later, when he walked through the slightly open bathroom door, to find Sirius sat on the edge of the bathtub. His hands were shaking so violently, fumbling with the buttons on his pyjama shirt, struggling to do it up. He hadn’t even noticed Remus walk in. He watched for half a second, before walking over, putting his hands over Sirius’, squeezing them once.
“Pads?” Sirius glanced at Remus, who was crouched on the floor in front of him. “What’s wrong?”
“I-“ there were tears sparkling in his eyes. “I don’t want to be like her, Moony.”
“Like who?” He said, trying to get some sense out of his panicked boyfriend.
“I- I hurt him. I don’t even know what I sent out my wand, I-“ oh.
“Love, listen to me, okay? You’re nothing like her. It was an accident, yeah?”
“But what if- what if one day I-“
“You won’t. I know you won’t.” Sirius finally reached his limit, breaking down as Remus wrapped his arms around him firmly, pulling him close, off the edge of the bathtub.
Sirius, still shaking, wound his arms around Remus, burying his head into Remus’ collarbone and sobbing quietly. Remus rubbed his hand up and down Sirius’ back, pressing a kiss to the top of his head.
“You spend every full moon as a dog to stop me from tearing myself apart, love. You spend every minute of every day making sure that everybody else is okay. Everything about you is incredible. You’re amazing.” Another sob, as Sirius tightened his grip on Remus silently. “Besides.” Remus started with a small smirk. “You haven’t married your cousin.” Sirius laughed then, pulling his head back to look Remus in the eye.
“No, I have you.” His eyes widened almost immediately after he’d realised what he’d said, previous concerns forgotten. “Not that- not that we’re, uh, I just mean- I just mean I could see myself marr- actually, forget I said that-“ Remus cut him off with his lips, one hand on his face, the other clasped in Sirius’. Sirius let out a muffled noise of surprise, before melting into it.
“You’re rambling.” Remus murmured with a smile as he broke the kiss, his breath ghosting across Sirius’ face. “I could see us married one day too.” Remus said in a low whisper, and Sirius’ face, still slightly tear stained, split into a grin.
“Seriously?”
“Well, yeah. A half blood and a blood traitor.” Remus said casually, squeezing Sirius’ hand reassuringly. “Match made in heaven.” Sirius laughed again, the tension leaving his body. “Feeling better?”
“Thanks Moons. Really.”
“Anytime.”
“Why- why does she still get to do this to me? I left. She shouldn’t be able to make me feel like this anymore.”
“I wish she couldn’t. She never deserved someone as incredible as you.” Sirius swallowed, at a loss for words.
“I love you so much.” Was the only thing he could think to say, earning him a heart melting smile from Remus.
“I love you too. Match made in heaven, remember?”
“Written in the stars.”
“You are the stars.”
“And you’re my moon.” They both jumped at the sound of a pounding on the door.
“Can you two stop being saps and open the door? I need to brush my teeth!” James shouted. Remus and Sirius’ eyes met, and the two of them burst into a fit of laughter, foreheads pressed against one another.
“We should probably…” Remus started, standing up, pulling Sirius up with him.
“Right, yeah.” Remus pulled Sirius into a quick hug, as Sirius murmured a small “thank you,” before opening the door.
They knew, after leaving that small bathroom in their dorm at Hogwarts, that no matter what happened, no matter where they went or what they went through, they knew it would all be okay, as long as they had each other.