Some nights Oliver lies awake for hours just staring at Zosia, whilst running his hand through her hair. He watches her sleep, looking so peaceful, so happy, as her arm lies across his chest, as she holds him close. He finds it hard to believe that someone like her could chose him.

Those are the better nights.

The darker nights creep in: Penny's Birthday, his first wedding anniversary, their anniversaries. She understands, she's a beautiful and caring woman who maybe struggles to express her feelings but nevertheless, she understands. She knows what he is feeling. But she doesn't judge. She doesn't even let on sometimes when she can tell he just needs to think. So, she curls up with her head on his chest, her hand covering his scar from the surgery that saved his life, that gave her the chance to meet him. She sleeps and lets him lie awake looking down at her, not in wonder, but in fear.

If its really bad he can't bare it and has to slip out. The last person he got this close to died. He can't let it happen to her. He can't lose her. Maybe he's just a fire and when beautiful moths fly too close they burn. Maybe he isn't supposed to be in love. Maybe he is supposed to live alone.

On nights like these she usually comes and finds him. Its unexplainable, as scientists they never really try to explain it, but on the darkest nights she knows. She wakes up, she finds the sheets still warm, for he has never left long, and she goes and finds him. Sometimes he's in the kitchen, other times the bathroom. Once she caught him just as he was opening the front door. She covered his hand with her smaller one and pried it off the handle before linking his fingers through hers. Then she led the way back to their bed where she would whisper to him that she loved him. She chose him. He wasn't going to lose her.

And it helps. It helps most of the time. Usually he's too tired to put up much of a fight anyway but hearing her say those words helps. But sometimes it doesn't.

On one night in particular, the day of Tara's birthday, as he is doing his daily ritual of letting Zosia fall asleep first, a terrible wave of guilt hits him full force in the chest. His hand ceases the stroking of her hair, his heart seems to stop beating, his head starts to spin. He can hardly breathe and just needs to get away. So he slips out of bed, being extra careful not to wake her, and stumbles into their living room. Immediately he finds the window, opening it and putting his head out, breathing in the fresh cold air.

He feels like a monster. Like he is betraying both of them at the same time. It hurts. Everything hurts. He turns and makes his way into the kitchen fishing in the cupboard for a glass and turning on the tap. Maybe it's that that wakes her, or maybe its just the feeling, but he startles when he hears a quiet "Hey."

When he turns, he finds her framing the doorway, her hair a tangled mess, her eyes hardly open but a gentle smile on her face. "Hey," he replies before turning to pour himself his drink.

He takes a few minutes, to fill the glass, then take a few sips, before gulping the cold liquid down. He gives them both a few minutes to think.

When he looks at her again he realises that she is more awake. Her eyes wider open, her frown lines deeper, as she walks towards him but stops at the couch.

She drops to sit, with the grace of someone who was asleep just minutes before, and he knows that it is his cue to join her. So he does. Despite the feeling of pain still holding him, he goes and he sits and he just stares at her because he has no words.

Luckily, she does.

"Babe I'm sorry." She reaches out and takes his hands. This is how most of their conversations start and serious arguments end. They are both better at communicating by touch. Such as right now when her thumb strokes his knuckles letting him know that she is trying to calm him down that she knows he is in pain. "I'm sorry I never realised what day it was sooner."

He shakes his head. No. It's not her fault she shouldn't feel the guilt. It's his. But her hand tightens its grip.

"I'm your fiancé. I should know these things. And I am sorry Ollie. "

She waits for him to nod in acknowledgement, not acceptance, before she continues.

"I'm going to be honest here, I don't really know what to say," she tries to catch his gaze and he lets her, if they are being honest then she can see the pain he knows his eyes must show. "But I want you to know that what you are feeling, is okay. Its normal and it is okay. I don't love you any less because you loved her, your allowed to admit that you did. I have a ring on my finger that promises that for the rest of our lives we will love each other. That's the future, and that's all I need to know. I love you Oliver Valentine and I know you are scared, that love will means loss to you, but I want you to know that even if it did, if loving you meant pain, then I wouldn't change a thing."

He looks up at her at that. His hand squeezes hers and she can see in his eyes that he is begging her not to say that. She can see the pain that the thought of losing her brings him and she has all the clarification that she needs. He loved Tara, but he loves her now, and that's all she cares about.

"For someone who didn't know what to say, you said the right things." He mumbles, leaning forward to rest his forehead against hers. She smirks, that cheeky look she gets when she knows that she was right. It makes his heart beat again for all of three seconds before it forces it to crumble. "Please let me die first." The words fall from his lips by accident. It's a plea he has prayed for but wanted to hide from her and he can see, as her face falls, that his reasoning behind it was accurate.

"Oliver-"

"Sorry I shouldn't have said that we don't get a choice I'm sorry I-" His breathing start to quicken again he can't even pretend to know what he is saying, he suspects she will have no idea, but she does.

"Shhh" she hushes him her hand now reaching out to stroke his hair. She moves closer when he leans into her palm. Letting him drop his head to her shoulder. "I promise that I will do my very, very best to never, ever leave you," she seals her promise with a kiss to his head which he returns by placing a gentle one to her lips.

They sit holding each other for some time. Maybe its been seconds, maybe minutes, it could be hours, but the feeling of pain slowly eases from his body. She can feel the tension ebb away and when eventually he relaxes against her, she smiles. This wont be the last time something like this happens. The are both damaged and not very good at talking things out. They bottle it up until the dam breaks. Tonight it was him, she knows next time it could be her. Words don't often help their pain. They're doctors, they've given out too many platitudes and false promises to be convinced by them anymore. But by touch, by holding the other and by simply loving each other: they will heal.

"Thank you," he whispers as they break apart.

"Always," she replies, tugging on his hand as she rises to lead him back to their bed.