If it's not supposed to be, why does it feel right?

Part 1.

It was Regulus third year at Hogwarts. "Oh please Reggie. It will be great. I promise.", his older brother Sirius pleaded. Sirius has been trying to convince Regulus to come to the Potters with him for the last three years, which annoyed Regulus, because the years before Sirius straight up ignored him. He never owled or visited. "Come on Baby Black", James Potter said with a stupid grin. James was Sirius best friend, since the day they met,which is why Regulus got used to also being bothered by him. "Fine. But I'm only agreeing so you two leave me alone.", Regulus gave in, "Finally! Took us only, what? Three years?", Sirius high-fived James. Regulus rolled his eyes and returned to his book. The older boys exchanged a look and let the boy be. They did not know what could be more interesting in a book than in them.

Regulus let out a sigh as soon as the boys left the room. He was relieved that he didn't had to go back to his parent's household for this years Christmas. Not just that his parents had started to disagree and fight about everything, but his father had also become abusive. Not emotionally as he used to be since Sirius and Regulus were little kids, but physically. Sirius had the luck to never feel the hit of Orion Black, because he decided to never return to the black manor after his parents disowned him for getting into Griffendor, but Regulus had his struggles to recover from his bruises and black eyes.
Potter seemed to have angel like parents. They loved him and took Sirius in almost immediately.

Regulus enjoyed the idea of spending Christmas with his brother after five years once again. It seemed to warm him from the inside. And if he liked it or not he also had grown comfortable to James presence in the past years. —But he would never admit that. To no one. Not even to himself.— That was actually what was freaking him out so much, the thought of loosing his brother —again— and loosing his favourite enemy on the quidditch pit. Spending a nice time with the two of them, just for them to maybe go back to ignoring him-  Regulus pressed his hands to his ears to stop himself from overthinking. His face looked as if he was in bad pain. 'We are going to have a nice time.', Regulus told himself.

"Regulus are you okay?", Pandora said, she was Regulus best —and kind of only real- friend. Regulus looked up at her a bit confused. He didn't realised she came up to his table in the library. Regulus decided to play it off. He shrugged and said, "yeah.. I just have kind of a headache.", Pandora looked at him a bit worried, she did not belive him. But then she nodded and said, "come on let's go grab some dinner.", the slytherin smiled at her, "sure let me just put my book", he closed the book he was reading in, "back to its place.", Pandora caught a glance at the cover, "since when do you care about slow motion potions??", she asked, "Regulus looked at the cover and let out a scoff, "I don't actually. I was looking for a book about the potion I have to write an essay about, but then my brother and his best friend came in and I needed a cover.", Pandora raised an eyebrow, and let out a small giggle.

"Well let's go shall we?", Regulus said and offered Pandora an arm. She accepted the gesture, because that was the way they usually walked around. And they walked to the great hall. "So how far are you with that potion essay anyways?", Panda asked after a while, "not far at all. I wanted to start today but we'll, let's say I got distracted and grabbed the wrong book.", Pandora broke out into a laughter, which wasn't loud, but two specific guys saw it immediately and felt something in their stomachs. A feeling they couldn't describe, but also didn't know where to order it. Sirius looked up at his brother and grinned widely as he saw him with a girl, smiling at her. Seeing in his eyes that he cared for her. Sirius pressed his elbow practically into James, "look! look at that!", he exclaimed. James snorted, "what? Your brother has a friend?", Sirius shook his head, "no look. He cares about her.", James smile twitched a bit, "you don't know maybe he just likes her as a friend.", Peter Pettigrew, also one of Sirius best friends, decided to join in on the conversation. "Maybe. But Reggie doesn't care about people. And I just always thought he was gay.", Sirius said not taking his eyes of his brother and that girl.

"As if you would have something against that.", now also his boyfriend, Remus Lupin, decided to go against Sirius. "No not in that way- oh man. You're all getting me wrong. I don't have anything against gays-", Sirius winked at Remus, "obviously. But I don't know. I just am happy for Regulus.. I guess." 

"They're not dating.", Lily said, which made James' arm reach into his hair almost like a reflex. "And how would you know that?", asked Sirius, not believing that Lily Evans could know something about his brother that he didn't. "You see the girl. Her name is Pandora. And she has been going out with Xenophillius for quite a few weeks now. And I simply don't believe she would date two people at a time. Plus your brother seems way to comfortable around her.", Sirius nodded and frowned a little, " I was just happy for him"