Chapter 1
The first time they hooked it up it had felt like a fever-dream to Sirius.
He wasn't sure his advances would work, Remus Lupin was his brother's best friend and he was also just so damn proper.
Sirius was 8 years old when fell in love with Remus the first time he saw him.
New to the Potters' household, new to a loving home, new to a place where he was loved and appreciated, it was scary to meet someone like Remus—someone so tall and beautiful, with kind eyes and a genuine smile. He had broad shoulders and a wiry build even then. He remembered standing on the platform with his parents after James and Remus got on the train to leave for boarding school and all he could think about was Remus.
He somehow missed Remus, someone he had met once, just as much as he missed his brother that year and every other year after that until he got to go to boarding school himself.
Now, 10 years later, he was somehow more beautiful and perfect-looking, and Sirius couldn't get enough of him.
It had all started at James and Lily's engagement party; all night, people had come up to HIM, congratulating him on his new family member. It really sunk in, he was a Potter and his older brother James was going to marry the woman he'd been in love with since HE was eleven.
Sirius was so happy for his brother, his parents, and himself. He accepted every drink offered to him in toast.
James passed out before the party ended, and Remus and Lily took him back to their room. Lily stayed with James, and Remus was walking back to the party, probably to help clean up or do something equally wonderful, when Sirius ran into him pleasantly buzzed and unable to hide his smile when he came upon Remus.
"James forgot his phone so I thought I'd run it over to them" he helped up James' phone and laughed
Remus smiled back at him so hard his dimples shown and for a second Sirius forgot how to breathe.
"c'mon I'll walk you to their room and then we can go back and help your mom clean up together."
They talked and walked the whole way. Sirius couldn't stop smiling he couldn't believe that this was how he was ending his perfect evening. Over the last few years he had spent a lot of time with Remus Lupin, enough for him to fall completely head over heels in love with them to the point of no return, but it wasn't often that they spent any time just the two of them. They usually had James and Lily or his parents around. The rare few times it was just the two of them was mostly when Remus tutored him in History while at Hogwarts.
When the night ended in the guest house where Remus was staying after 4 mind-blowing orgasms, a record for Sirius, he well and truly knew this was it for him. it didn't matter that he was 18 and off to college next year and supposedly going to meet a million people.
He knew Remus Lupin was the one for him.
He just needed to make sure Remus felt the same.
He tried to find an excuse to ask James for Remus' number, but he always backed out, so he was really excited about Lily's birthday dinner tonight.
He could barely contain his excitement or sit still and when the bell rang he knew in his insides that it was Remus.
He had carefully applied his eyeliner and made sure to dry his hair on the lowest setting to ensure the least amount of frizz.
He felt gorgeous.
In walked Remus Lupin and Sirius felt himself light up from the inside as he saw his mum hug him hello.
then suddenly Remus turned to the man that walked in next to him and introduced him to his mom as his fiancé
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Sirius adopted by Potters at age 8, James is 13ish
Remus breaks Sirius heart
then Sirius grows up and Remus finally admits to self he loves James' younger brother and works to get him back
HEA? Really your choice.
extra points if you can get baby Harry to help Lily be matchmaker