Things had been going so great since the end of the Dark War. Everything seemed to fall into place. Jocelyn and Luke had gone on their honeymoon that night, and would be gone for at least the next three months. Simon had started his shadowhunter training, and his memory was coming back little by little. Jordan's death had meant that Simon was alone in his apartment, so Isabelle had convinced him to move into the institute, where Clary was staying until her parents got back. Alec had moved back into Magnus's apartment, and Robert and Maryse spent almost all of their time in Idris, trying to help the Clave repair the damages Jonathan's endarkened had caused on the beautiful city.

And Jace? Her relationship with Jace was moving steadily forward. They spent most of their time together, including their nights. He continued training her and teaching her everything he possibly could about the shadow world. They were inseparable. Which was exactly why it felt as if she had been stabbed with a seraph blade when she found him in bed with Aline.

Flashback:

She had told him she would be at an art class, but she had really traveled to Alicante, to pick up the present she had bought for him. Not that it was his birthday or anything, but she had seen it in passing, and just had to get it for him. She had even had it engraved.

She couldn't wait to see the look on his face when he saw it. She had drawn a portal as fast as she could, and walked quietly, intending to surprise him.

Unfortunately, she had been the one to gasp in surprise when she opened the door to see Jace and Aline on the bed, naked, in the full stages of sex. Even more unfortunately, they were completely uncovered, so she saw everything. EVERYTHING. Not only was she heartbroken, but she was scarred for life.

Jace had looked over at the sound of her gasp, and sprung up, tossing Aline aside like a rag doll. "Clary! I- we-."

She turned. And ran. LIKE HELL. Unfortunately, that doesn't mean much when your boyfriend is faster than Sonic-X. He had caught up to her before she could reach the elevator, calling her name. She bolted for the stairs, grabbing her stele and drawing a speed rune on her wrist, not a second too late. His fingers brushed her forearm, before she sped up. When she got to the bottom, she slammed the door shut, gaining her a minute or so, as he was thrown off for a moment.

She ran through the sanctuary as fast as she could, trying to ignore the steady flow of tears that streamed down her face. However, before she could make it through the doors, they opened, and the entire gang flooded in. Isabelle, Simon, Magnus, and Alec all paused as she skidded to a halt, looking for another exit.

Isabelle sucked in a breath. "Clary?! What-"

"Clary, wait!"

She whirled as Jace stopped in front of her. His hair was tousled, his lips were swollen, and he had at least two hickeys on the right side of neck. He was half-naked, his black boxers being the only thing keeping him decent.

She let out a sob, stepping back and putting her hands to ward him off. "Don't- please just-".

He cut her off, his eyes watering as he grabbed her hands. "Clary, please! Just-".

"DON'T TOUCH ME!" She yanked her hands out of his, pacing back and forth, her hands pushing her hair out of her face, before looking up at him, betrayal shining most brightly in her eyes. "How could you?! After EVERYTHING we've been through, how could you do this to me?!"

"Clary, please just hear me out! I can explain! I- Aline and I-".

She held up a hand, cutting him off again. "I can't listen to you talk right now. I just need a moment to get myself together."

She started pacing again, her hands running through her hair, as she tried to keep her level of hysteria down. She wiped her tears on her exposed wrist, glancing back at the others who were watching with mixed expressions, before shaking her head. "I, uh… I think I need a break for a while."

A tear rolled down his left cheek. "Clary… please just hear me out."

She shook her head. "I don't want to hear anything right now. I just need to know… do you still love me?"

He took a step towards her, a silent sob escaping him, as he cupped her cheeks. "Of course I do. I'll never love anybody other than you. You're my entire life, Clary. My everything. I'm nothing without you... I love you so much, it kills me."

The tears streamed, as she put a hand over one of his. His thumbs brushed away her tears, as she looked up at him, blurry-eyed. He bent down, brushing his lips against hers, resting his forehead against hers.

She stayed like that for a while, before stepping back. "I'll come back. If you really do love me, then I'm sure we can work this out." She took the hand that was still pressed to her hand, and put the sheathed sword in it. "This is my promise to you."

She looked up at him one last time, before turning, smiling quickly at the others. "I'll keep in touch. I promise."

And she ran.