This was written for Then There's Us on LJ. The picture prompt was a key on a note that said, "I cannot forget that I am in love with you. I'm sorry. Here's your key." This is what resulted.
He wandered the room slowly, taking in a year's worth of memories. Some of them were good. The picture of the two of them and little Tony playing on the beach. That was a good memory. A brilliant one, really. One of the few days she'd let her guard down around him. The vase with the flowers he'd only just recently bought her. In some ways, he supposed that was a good memory, though in the end they hadn't done any good. There was the sculpture she'd bought for the flat on a rare, impulsive whim. The goddess entwined with her lover had been such a romantic addition to their home, he couldn't help but think that there was hope for them yet.
But there were so many bad memories. The patched spot on the wall from where a fight went too far and he'd angrily punched a hole there. Knuckles had been bruised for days. That was definitely a bad memory. The dried bouquet she'd caught when Jackie and Pete had renewed their vows should have been a happy memory, but the argument they'd had afterward about him proposing just made it rank up there with the awful ones. The one that hit the hardest was the empty coat hangers by the front door. The familiar blue leather jacket was gone, grabbed in a rush as she stormed off to her mum's.
A part of him had known all along they wouldn't work. They'd tried so hard in the beginning. Tip-toeing on eggshells around issues that they once would've had out long ago and forcing displays of affection when they weren't being felt. He dutifully appeared by her side at Vitex appearances, despite his reserves about doing so. And she allowed him into the perfectly built world she'd created at Torchwood, even though it nagged at her pride to let someone more knowledgeable than she was in. From the outside looking in, they were perfect.
But the Time Lord who'd left them behind on the beach still hadn't fully disappeared, and likely never would. His presence lingered in everything they did. When he kissed her, a voice lingered in his mind that said he wasn't the one she wanted to be kissing. Every time they got into the car, he could almost feel the annoyance radiating from her saying that it would be so much easier traveling in a TARDIS. From time to time, she actually came right out and said he'd never compare, usually when she was angry and he was being daft for some reason or another, but it was enough to drive the point home. As long as he only had one heart, and got wrinkles and the occasional gray hair, and couldn't jet-set her around time and space, he'd never be the man she'd fallen in love with.
But his heart, the sole heart that it was, and his memories still pointed to her. As far as he knew or understood, he was still the same. She was the woman who'd put him back together after he'd given up everything in the war. It had been her smile that had driven him to keep going; it was that wide, even-toothed grin with the tip of her tongue peeking out between her teeth that had allowed him to heal. Her innocence had been an important part of his daily life, and as she'd grown into a clever and resourceful adult, he'd fallen in love.
For so long he'd thought he'd lost her. And then there it was, the chance to have her. Completely have her, every single day for the rest of his extremely shortened life. Every day, living as normal people. Or, at least, as normal as two people who chased down aliens for a living could ever be. There could be a mortgage, a fence, a dog, and maybe someday even a family of their own. It was too good to be true. And that should've been the first sign it would all go wrong.
He had to leave. He couldn't keep hurting her, intentionally or otherwise. She didn't love him. Maybe she never would. Or maybe someday she'd realize that she was still his entire world and that, while he couldn't show her the whole of space and time, he could still love her. But he'd have to be gone for that to happen. They couldn't keep living this way.
Closing his eyes to remember how to breathe, he took the key from the ring he kept in his far too small human pockets. It joined the note he'd jotted down on the credenza. They both sat where she usually carelessly tossed her own keys when she came in at night. He took another long look around the room, at the couch where they'd curled up and watched telly together and at the kitchen table where she'd eaten more than one of his experimental meals. They could have been so good.