I rewrote parts of the story, especially the ending to make it true to the series. In this story, the two are only a year apart, Bellatrix being the elder. This takes place in Sirius' sixth year, and Bellatrix is on the brink of joining forces with Voldemort and the like, harboring prejudice against muggles and muggleborns. Title and lyrics from Long and Lonely Road by Hawk Nelson.
I know it is so hard for you and I to be apart
I'm slowly fading, you're my lady
That keeps me moving on
It's a long and lonely road
It's a long and lonely road
If you don't like it
Then please don't take it
It's a long and lonely road
Sirius came back from another of their encounters and harshly punched the wall. His face pulled into a grimace. "I don't know what I am doing, Prongs."
"Bellatrix again?" James inquired to the other boy in the room.
"Of course. Who else could possibly do this to me?" Sirius was silent for several minutes before he glanced back at James. "Can I tell you something?" Sirius took his best friend's nod as all the encouragement he needed to continue.
"We were betrothed when we were four and five. We were inseparable when we were younger, always finding adventure and getting into trouble. Our mothers reprimanded us constantly for not acting our status and setting a horrible example for Narcissa and Regulus. Somewhere along the way, I fell in love with her. Then she went off to Hogwarts, and I was to follow her the coming year. No one planned on me being sorted into Gryffindor.
"We fight all of the time, but we don't actually hate each other. I think she is upset with me because she thinks I abandoned her, and I cannot stand the ones she aligned herself with. She was my first everything. First kiss, first time, first love. I need to do something about this right now before it is too late and cannot be fixed."
James took in his confession, and asked gently, "Are you still in love with her?"
"I don't know anymore."
James looked at his best friend with an unreadable expression on his handsome face. "Is she the first thing you think about when you wake up each morning?"
Sirius seemed as though he was trying to justify something to himself, but gave up and simply replied, "Yes."
James sighed and nodded. "Then you need to make up your mind about going after her. I can't honestly say that I am perfectly comfortable with the whole idea, but I do understand. We were raised in the high society, with old traditions and beliefs. You belong to one of the oldest surviving bloodlines of our world. It was instilled in you since birth that your family was different from the others, and truthfully, it is. You can't help who you love, Sirius, and you know that I will always back you up with your decisions, no matter how insane they might be."
Sirius smiled fleetingly before jumping up and rummaging around in his trunk. "James, I have to see if I have a chance. I need to know if she feels the same, otherwise I have nothing left for me in my family."
"Good luck, mate. All of the good luck in the world," James said, handing over his cloak and the map.
Sirius grabbed them, and stuffed something into his pocket before dashing out of the dorm and passing through the common room to the portrait.
Sirius did not need a map to find his cousin, knowing exactly where she would be after a fight. He found her perched on a window ledge, gazing at the moon, looking every bit the beautiful aristocratic girl she was. Approaching cautiously, he placed a gently hand on her shoulder, causing her to whirl around in surprise. Sirius was shocked to see tear tracks marring her pale cheeks, and she was just as shocked at seeing him next to her.
"I am sorry," he whispered, not daring to break the calming silence too much.
"Sirius," she began, but he cut her off before she was able to go any further.
He laid a finger on her lips. "No, Bella, listen. I am in love with you. I am so in love with you I don't know what to do. I need you to make a choice, right now. If you love me, then stay with me, and we will get married, just as our parents had planned for us those many years ago. We would be the perfect match, an amazing couple. Everyone would benefit; we would be happy, our parents could ensure the wealth stays in the family and that the line continues. However, if you choose to follow Voldemort, I cannot support your choice, and I will leave. There is nothing tying me to my family, nothing except you, and if you will not be with me, I will run away for good.
"So Bella, the choice is up to you. You told me you loved me once. If you do not want me, I will walk away and never look back." He caressed her cheeks with his fingers, brushing away the newly formed tears that fell from her eyelashes.
"Siri, don't make me choose. Please don't do this." Bellatrix's dark eyes met his grey ones.
Sirius bent his head and quickly captured her lips in a sweet kiss, hands tangling themselves in her black hair, identical to his own.
She pulled away shakily, turning her gaze to the bright moon.
"Siri, I love you, but I cannot give up my beliefs for you. My Lord stands for something, he can give me power, power no one else has. Join us, Siri, make a name for yourself in this world."
Sirius stared at her, his heart shattering into a million pieces, although he would never admit it. He kissed her again, opening her mouth to him, stroking her tongue with his. The kiss seemed to go on forever, and when it ended, they were both breathless.
"Is this goodbye?" She asked him, almost afraid of the answer.
He nodded, pulling a small box out of his pocket. He slipped a beautiful silver ring out, pushing it the middle finger of her right hand.
"To remember us by, to the good old days of our youth."
Sirius stood up, and left her in the corridor, slowly making his way back to the Gryffindor common room. That summer, he left home for good and moved in with the Potter's, never imagining that the woman who had taken over his life would be the one to end it.