(A/N): This is pretty much pure angst, I warn you now, set after the "I've never been so cold" comment and diverging from the episode from there, set about a month or so after. All because I was listening to Taylor Swift, hence the title. Good luck, I own nothing.

The Moment I Knew

"Morning."

Nikki didn't even look up at Jack's greeting, keeping her eyes solely focused on her work as she penned in the details for another report. Nearly a month had passed since what she mentally dubbed 'the day' in her head, the day her world had ended, or at least when she thought it had. Ever since Jack had found out about Ollie, he'd been acting off with her. She didn't blame him for that, not one bit. But she had silently vowed to herself to keep trying, to see if she could keep hold of her friend even if she might have lost her perfect match. And try she had, greeting him and including him wherever possible, making him tea the way she knew he liked it (and the way she'd gotten used to), trying to engage in meaningless small talk despite not being particularly good at it. She'd thought it had been working, albeit slowly, that he'd been thawing towards her a little. Until last night anyway.

She saw Simone glance between them from the corner of her downturned eyes. The ecologist knew far more than she should, but Nikki blamed herself for that too. Simone cleared her throat awkwardly. "Morning Jack. Where were you last night?"

Nikki held her breath unconsciously, half glad Simone had found the courage to ask the question and half dreading the answer. She wanted to hear what he'd say before he realised why the younger woman was asking, before he came up with excuses she didn't want to hear. If she'd ever needed a sign that she was never getting Jack, her Jack, back again, last night had been it.

"Nowhere really, went to a bar for a few hours, I think. Why?"

Her blood ran cold and she could feel Simone staring at her in concern. A bar, he was at a random bar. "I left a file in the viewing room," she stammered out, leaping from her chair and all but fleeing the room, though she headed to the locker room rather than the viewing room for more privacy.

Reaching the room, she made sure the door was shut behind her before she sank to a seat on the wooden bench dominating the middle of the space. Her breath coming out in short pants as she pressed her palms to her eyes, willing herself not to cry. She'd lost Jack forever. And all for a stupid, drunken mistake. For if there had been any hope, any whatsoever, Jack would have been at her birthday party last night.

Nikki stepped out of the cab, glancing up at the pub sign to make sure she'd gotten the right venue. Clarissa had called her a couple of weeks earlier to inform her that she was having a party for her birthday whether she liked it or not, and the former forensic technician was organising the whole thing, all Nikki had to do was invite Simone and show up herself. She'd fought for a few minutes but Clarissa had a habit of bending people to her will and she'd found herself asking Simone that very same day, Jack piping up that Clarissa organised the best parties and he wouldn't miss it for the world. His words had kindled a tiny spark of hope inside her and she'd found herself dressing with unusual care that evening. Perfectly curled hair, smokey eye and deep red lipstick. A dark red dress she'd been saving for a special occasion and matching heels.

Nikki laughed bitterly, the brittle sound echoing round the room. All that effort, all that hope, completely wasted. Worthless. Clarissa had pulled out all the stops, invited all the people she'd known Nikki liked and was friends with. Even Conor had been there, delivering an apology from Cara, who was still grounded after her mum had worked out where her seventeen year old had disappeared to for a few weeks. But the only person she'd wanted to see, wanted to be there, was Jack. She nearly laughed again. The one person she'd wanted to see wanted to be nowhere near her. Didn't that just describe her life to a tee?

"I'm sure he'll be here soon."

Nikki blinked in surprise as Simone appeared at her side, joining her in none too subtly watching the door for Jack's arrival. "I don't know what you mean."

"Of course not." Simone rolled her eyes. "I still have no idea what's gone on between you two, but he's really coming round now. That much I do know. He even bought you coffee yesterday." She grumbled goodnaturedly. Nikki managed a tiny smile. Jack had refused point blank to ever buy Simone a coffee thanks to the latte she'd spilt on his desk her first morning with them, and he'd stuck to his word. But he had shown up the previous morning with two coffees and though Nikki had expected the second one to go to Simone, she'd been pleasantly surprised when he'd placed it down on her desk with a fleeting smile.

"I screwed up." Nikki summarised quickly. "I don't think it can be saved, though I appreciate the optimism."

"You've nothing to worry about." Simone countered confidently. "He'll be here any moment, you'll see."

Nikki tipped her head back to try and blink back the tears. Her palms were no longer sufficient to keep them at bay. Simone's confidence had been appreciated at the time, but now it just felt cold and empty. Empty, like her. Except the gnawing, clawing pain in her chest. But she'd had that since the moment she'd realised he wasn't showing up.

The bathroom was cool, a welcome relief from the stuffy function room, and Nikki took no small comfort in the chance to cool down a little. It was nearing midnight and she'd just seen Conor safely off home in a cab. The older man had offered her a gentle smile as he'd wrapped his arms around her. Conor knew; she knew he did. But the man had never judged her for what she'd done, for what she'd put his son through, and had stayed in touch much as they'd done ever since Thomas had died. She didn't know if Jack knew his dad was still in regular contact with her, for neither had ever mentioned it. She braced her arms against the sink, trying to suck in deep breaths even as the tears slipped down her cheeks. There was no way Jack would let his father catch a cab home alone if he'd intended on showing up to her party. That was the moment she'd realised. She'd lost him, truly lost him.

"Nikki?" Nikki whirled round at the sound of Clarissa's voice, wiping ineffectually at her eyes as she saw Clarissa entering the bathroom with Simone directly behind her, both nothing but concerned for her. "Oh Nikki. I think I can guess what this is about."

"Can you?" Nikki let out a choked laugh through her tears, slipping down until she was sat on the cold floor, uncaring that she was probably ruining her dress by doing so. "I really don't think you can guess just how badly I messed everything up Clarissa."

"It can't have been that bad." Clarissa tried for comforting, but blinked in surprise at Simone's warning expression. "Come on, Nikki. Jack probably just had something run late."

"We all finished early because the case was finished, but I appreciate what you're trying to do Clarissa." Nikki buried her face in her hands. "I slept with someone. I was with them when Jack and Simone were at the care home."

"Were you still with Matt?" Simone asked curiously, crouching down beside the distraught blonde. Nikki shook her head miserably, still hiding behind her hands. "Then I don't see the problem."

"It was partly who I slept with."

"It's your life Nikki, I can't see Jack…" Simone's eyes widened as realisation dawned. "Wait, was it the student? The one that kept waiting for you?"

"The student?" Clarissa sighed as Nikki nodded slightly. "Oh, well yes, that would do it. But Jack would be more likely to be angry on behalf of your job being at stake, not with who you slept with Nikki."

"I kissed him." Clarissa and Simone turned to stare at Nikki in shock as she lifted her head slightly from her palms. "Well, it was sort of both of us, but I definitely started it."

"Kissed who? Jack?" Simone checked as Clarissa stared at her openmouthed.

Nikki nodded, more tears slipping down her cheeks. "At the care home, just before I sent him home. Only I didn't realise that Ollie was on the voicemail I'd left for Jack, asking me to go back to bed." She buried her face back in her hands.

"So that's what the cold comment was all about." Simone concluded thoughtfully, placing an arm cautiously round Nikki's shoulders. "I really don't think it's that bad."

"Don't you? I didn't tell him I broke up with Matt, then I slept with a student, kissed him, and let him find out about said drunken mistake from a voicemail." Nikki summarised brokenly. "I've ruined eight years with my best friend that could have been so much more and what for? Drunkenly faking an orgasm and wishing like hell I'd never gone to that party in the first place."

"I'm gone for a few months and all hell breaks loose." Clarissa shook her head in wonder. "Look, Nikki, as much as I know you're going to blame yourself, I'm betting Jack hasn't exactly been a saint either."

"He slept with Liz." Simone piped up unexpectedly, prompting all eyes to turn to her. "What? Liz text me and told me. A lot more information than I ever wanted to know about Jack in all honesty."

"It doesn't matter." Nikki shook her head stubbornly. "It's my fault and I ruined things between us. This is just me realising I was stupid to hope I could ever fix it."

Wiping at her eyes, Nikki stood and took a few calming breaths. Right, she could do this. She'd spent months pretending to be fine, like her life wasn't falling apart. All she had to do was get through a few hours and then she could cry at home to her heart's content. Steeling herself, she made her way back to the office, not looking at either Jack or Simone on her way back to her desk.

"Nikki." Jack's apologetic, almost desperate tone had her glance up involuntarily, spotting the remorse in his eyes in an instant. Just a shame hers were empty. "Nikki I-"

"It's fine." Nikki cut him off woodenly, not wanting to hear whatever apology he was about to come up with. After all, it was her own fault for getting her hopes up. "Really." She was lying through her teeth, but that wasn't the point.

"No, really Nikki, I-"

Nikki's phone ringing cut him off for a second time and she answered it with no small amount of relief, quickly writing down the address on a post it note. "We have a case."