A/N: This was written for xXStandingInTheRainXx's What You Would Never Write Challenge. My challenge was to write a Lily/Sirius fic, and after writing this, they are probably one of my favorite ships lol. ;)

Disclaimer: Everything you recognize belongs to JKR.

You Only Love Once

I heard a cry, waking me instantly. Harry. I lifted the blankets off of me, careful not to jostle the bed too much and wake James. I walked out of our room, my hand lightly brushing the wall to guide me through the darkened hall.

Harry's room was lit by the moonlight filtering in through the window, and I made my way quickly to his side, reaching down into his crib and lifting him into my arms.

"My precious baby," I cooed, bouncing him in my arms as I walked over and stood in front of the window. After a few minutes his sobs began to quiet, slowly turning into hiccups. I gently stroked his soft dark hair as I stared out the window into the moonlit night. There was a light layer of fog in the street, reminding me instantly of a night about a year ago. I heard a lone dog bark, and the sound sent tears falling down my face. I quickly wiped them away as best I could before they could land on Harry.

I couldn't believe that it was only a year ago, it felt like a life time – but it didn't matter how much time had passed, my heart had yet to heal.

James was gone, away for work, when I left the house, walking out into the foggy night air and apparating away.

I appeared in a moonlit alley, and moved into the shadows, hurrying down the edge of the road, silence around me, until I came to a bright green door that looked almost black in the night. I knocked on the door – three sharp raps – before glancing carefully around me. I hated this neighborhood at night, despite my magical powers. All of the houses were built cramped together, the doors – most of them with peeling paint – and maybe a small window, were all that showed on the face of the house. But there was something that I had to tell him, and dark creepy alley or not, he had to know.

The door opened and dark brown eyes that I would recognize anywhere appeared before me in the crack of the door. I saw a wave of recognition pass over those eyes, and then the door opened all the way.

"Lily," Sirius Black said, stepping aside so I could enter. I did so quickly and he shut the door behind me.

"I don't understand why you have to live in such a creepy neighborhood," I said walking down the hallway and into the living room, sitting down on the sofa. He stood in the doorway watching me, a half smile on his face, and my excitement of what I had to tell him returning in full swing. "Come here." He walked over and sat down beside me. Something was different about him today, something in his expression, but I couldn't place exactly what it was. "What's wrong?" I momentarily forgot everything that I wanted to tell him.

He scooted closer to me and ran his fingers through my hair before caressing my cheek. It looked like he was on the verge of saying something but then seemed to change his mind.

"Nothing," he said and leaned forward to press his lips against mine. "Don't worry about it." He leaned back and smiled at me, but I could still see the tight lines of tension in his face.

"You can tell me anything, you know that right?" I asked him, and he nodded in return. "You're still not going to tell me are you?"

He looked away, his mouth set in a hard line. "I don't know if I can… I should, but I really don't know that I can," his voice sounded broken, miserable, and it caused my heart to hurt a little at the sound of it.

I lifted my hands, placing them on either side of his face turning his head back to look at me. "I love you. You can tell me anything and I won't be mad at you." I gave him an encouraging smile, and he leaned forward to kiss me again.

"I love you too," he said, "which is exactly why I don't think that I can tell you." His eyes were pleading with me, begging me to understand.

There was a part of me that wanted to trust him, to just forget everything that had happened so far tonight. But I couldn't ignore the small part of me that was begging to know what was wrong, to comfort him in any way I could.

"I just hate seeing you like this," I said brushing the dark curls out of his eyes, and kissing him on the forehead.

He closed his dark eyes. "I know, and I'm sorry."

"Can you at least tell me what it has to do with?" I asked. "Maybe I can help without you having to tell me exactly what it is."

He let out a sigh, and opened his eyes, a few tears falling down his face as he did so. I felt my heart stop – this was the first time in my life that I had ever seen Sirius Black cry. I gently brushed the tears from his face, but more came down replacing them. Without a word, I wrapped my arms around him, pulling him as close to me as I could. He wrapped his own arms around me, running his hands through my auburn hair. I could feel him trembling in my arms, and that was when I really started to worry. What could be so bad that Sirius, my brave Sirius Black, was reduced to tears?

"James," I heard Sirius whisper, and I instantly stiffened and started to pull away, afraid that James was here, but his arms held me tightly in place.

"What?" I asked, and he pulled away just far enough to look me in my emerald eyes.

"Are you really okay with what we're doing to James?" he asked me seriously. I felt an ice cold panic start to spread through me, and my heart began to quicken.

"Of course I feel terrible about what we're doing to him, but I love you Sirius. I… I don't think I could live without you." No, oh no. This was not going anywhere good. Sure, some people might say just break up with James and be done with it, but it wasn't that simple. Even if I wasn't with James, how could Sirius and I possibly be together without having to keep it a secret? Sirius would never be able to tell James that he and I were together, they were best friends, practically brothers.

"What are you trying to say Sirius?" I asked carefully, my voice cracking despite my efforts.

"I don't know if I can keep this up… if James were to find out about us." His voice broke and he closed his eyes. I leaned forward and rested my forehead against his.

"I know," I whispered. "I know. I don't want to hurt him either, but what else can we do?" He opened his eyes again and looked into my own.

"You know what we can do," he said so quietly that I barely heard him.

"No… no we can't." My heart was breaking in two. How could he possibly think this, let alone say it?

"This is wrong Lily, we have to stop this!" He pulled away from me and stood, walking across the room leaning his arm and resting his head against the wall. I dropped my head into my hands, tears falling freely.

"W- why are you d-doing this now?" I looked up at him, still facing the wall. "Why now? What was the point of any of this, if you're just going to end it n-now?"

He turned around, and I was startled to see just how upset he looked. Tear tracks streaking down his cheeks, his face twisted up in pain. "This should have never happened," he said so quietly, his voice unrecognizable, and I let out a sob.

"You don't mean that," I said fiercely. "You don't, you can't. No…." I stood up and walked toward him, stopping just a foot away. "No."

He ran his hand through his hair and looked away, letting out a loud sigh. "No… I uh… yes… I… I don't know!" He turned around. "God, why do I have to love you so much?" Hesitantly I stepped forward and put my hand on his shoulder.

"Sirius, why try and fight this? I hate having to keep this a secret too, having to hide, but I don't think that I could stand not being with you at all. I—" The rest of my words were cut off by him turning around and roughly pressing his lips to my own. His arms were around me in a second, and I wrapped mine tightly around his neck.

"No," he said a second later, pulling away. "No."

"Sirius, please. What's done is done."

He shook his head. "It doesn't matter, he's my best friend. It's over Lily." His voice was cold.

My heart shattered into a million pieces. "I love you, doesn't that count for anything?"

He hesitated, and I knew he wanted to agree with me, that he did agree with me. "No, it's over, can't you understand that?"

"No, I can't understand that. I love you and you love me, what more is there?" I was almost screaming now.

He turned away from me. "I think you should leave now," he said quietly. I stood there for a moment, waiting for him to turn around, to change his mind. But he never did.

I took a deep breath to steady myself, before slowly walking down the hall and to the front door. I waited for a few seconds, hoping to hear his footsteps following me down the hall, but when only silence surrounded me I opened the door and stepped outside. I waited for as long as I dared in this creepy neighborhood, praying he would change his mind, that he would come after me and beg me to take him back – which I would do in an instant. But he never gave me that option. I turned on the spot, apparating away.

It wouldn't be until the next morning that I would realize I never told him what I was so excited to say.

Blinking tears from my eyes I heard a soft snore and looked down at my son sleeping deeply in my arms. I bent my head and kissed his forehead. With one last glance out the window, I walked back to the crib and tucked him safely inside of it. His dark hair so much like that of his father, and in his face I could see the slight resemblance. But slight it must have, because no one ever suspected a thing. Never suspected that Harrry was the son of the only man I ever truly loved.

A/N: Hopefully there weren't too many run-on sentences -- I was having more trouble than usual with those when I wrote this. I hope you liked it, and always remember: reviews are love. =]