I was always under the impression that Theresa is a bit younger than Martin, so read this as Martin being around 37, and Theresa being 33-34.
Arthur is really good with kids because he basically is one
Martin stands on the patio, surveying the party. His garden is filled with friends and family - both his and Theresa’s – and everyone seems to be enjoying the rare sunny weather. He can’t help but laugh to himself when he spots Arthur sitting cross-legged on the grass, surrounded by a semi-circle of children as he animatedly explains the time they ‘flew over the polar bears’. Apparently he’s giving it a bit of embellishment, judging by the rather loud roar he’s just let out.
Douglas and Herc are deep in conversation with Mycroft, who seems to be toning down his usual air of grandeur in an attempt to fit in; he’s even left his PA at home. Martin’s mum and Carolyn are over in the corner of the garden, laughing at a stack of his baby photos, which Wendy seems to have produced from nowhere. He’s just wondering where his wife has gone when a pair of thin arms wrap around his middle.
“Sherlock and Molly are here.” Theresa murmurs in his ear, nuzzling her nose slightly into the back of his neck. He turns his head to meet her eyes, and is greeted with the sight of the other Holmes brother and his family entering the garden, waiting to say hello. Martin grins; Sherlock has been forced to leave his infamous coat at home, looking slightly odd in just a white shirt and dark grey trousers, carrying little Milo on his back. Molly looks radiant with her pale yellow sundress covering her baby bump – he’s heard people say before that pregnancy suits her.
“Happy birthday, Martin!” she says, holding her arms out for a hug, and Martin goes to her willingly. He’d always liked Molly, even taking her out on a date or two before realising the extent of her feelings for Sherlock. She’d insisted that he be the godfather for the new baby, and he had been only too happy to accept.
“Thank you,” he lets her go with a grin, winding one arm around Theresa’s waist. He turns to Sherlock, “I hope it wasn’t too much trouble driving all the way up here.”
“Ever since your friend took it upon himself to teach Milo how to play ‘Yellow Car’, let’s just say that long journeys are an adventure.” Sherlock raises an eyebrow as his son holds up a lemon coloured toy car and squeals “Yellow car!”
“And look at you, Miles – you’re so big! Nearly as tall as me!”
“That’s not very difficult, is it?” Sherlock mutters, chuckling when he receives a glare from the pilot. “Happy birthday.”
Later in the day, once Milo has located ‘his Arthur’ and clambered into his lap to share the steward’s slice of birthday cake, Sherlock pulls up a plastic chair beside Martin and makes himself comfortable. He’s been forced to roll up the sleeves on his expensive shirt, cursing his half-brother for being born in the middle of summer as he grudgingly unbuttons the cuffs and folds them back to expose his pale arms.
“Why couldn’t you have been born in winter?” he grumbles.
“I didn’t choose my birthday!”
“Wh- you did not!”
“Perhaps I didn’t, but at least I had the courtesy to be born in January instead of August.”
Once Sherlock is sure that he looks presentable, he leans back in his chair and watches his son interacting with Arthur. It’s only when he looks over at Martin that he realises the other man is doing the same.
“You must be so proud of him.” Martin says, somewhat dreamily.
“What, Arthur? Mm, at least he’s learned to share food now-“
“You know I’m talking about Milo.”
Sherlock studies the other man’s face. Something in his expression when he watches his nephew makes the detective pause before he replies.
“Yes. Very proud.”
Martin nods, turning his beer bottle absentmindedly between his fingers. His gaze flits over to Theresa and Molly, who are also deep in conversation. As he watches, Molly takes his wife’s hand and gives it a squeeze, and he’s positive that they’re discussing the same subject that has been rolling around in his head for the past few months.
“Still no success, then?” Sherlock at least has the decency to keep his voice low. Martin shakes his head, flattening his fringe down over his forehead, a tell-tale sign of just how stressed he is.
“It’s been nearly a year, and nothing.”
“It’ll happen, Martin.” The detective is trying his best to do the whole ‘reassuring big brother’ thing, but Martin scoffs.
“That’s easy for you to say! One kid already and another on the way – not all of us have it as good as you do.”
He’s trying not to feel bitter, he really is; but when he sees Sherlock with his perfect family, and his well-paid job, and his frankly inhuman good looks, he can’t help but feel a pang of jealousy.
“Are you forgetting that you’re now a member of the royal family of Liechtenstein?”
The pilot shoots him a look.
“I may be married to a princess, but I’m still working as an underpaid pilot in Fitton. The only reason I get paid at all is because my wife owns part of the airline!” he sets his bottle down with far more force than necessary, “And none of this is helping me get her pregnant, is it?”
“You seem to think that my family is idyllic, yes? But it seems to have escaped your notice that it’s taken four years for Molly to conceive again.”
“Right, and how long did it take for her to conceive Milo? A few months, six at most? Here I am, nearly 12 months in and I’ve got nothing to show for it. No baby, not even… two pissy little lines on a white stick.” He covers his eyes and lets out a shaky breath.
“I’m sorry. I don’t mean to snap at you, but everything’s always been so easy for you and Mycroft, and I know it’s selfish – but when’s it going to be my turn?”
Sherlock is briefly stunned into silence; he’s never seen Martin this on edge before, let alone heard him swear.
Martin lets out a humourless laugh. “I’m fine, really. I think being surrounded by all the kids has got my back up, I’ll be alright later. I feel really bad for acting like a spoiled brat when all you’ve done is come to celebrate my birthday with me. Sorry.”
“Martin, I think you might want to-“
“It’s alright, just ignore me. Do you want a drink? Some food?” Martin gets up without waiting for an answer, and starts making his way across the garden. Sherlock watches as he crouches briefly to talk to one of Simon’s little girls, tickling her under the chin and grinning as she giggles. He watches Theresa appear at her husband’s side and whisper something in his ear, but gets distracted by the appearance of Molly. She takes the seat that Martin had vacated, leaning back with one hand on her stomach to get comfortable. Shielding her eyes from the sun with one hand, she mutters,
“I take it I wasn’t the only one who found it obvious, then.”
“Of course not. I knew as soon as she opened the front door. Martin’s just a little bit slow on the uptake.”
“Bless him; I think he’s just about catching up.”
They locate Martin and Theresa in a secluded corner of the garden, out of earshot of everyone else. The princess is clutching her husband’s hand and talking very fast, while he just looks completely dumbstruck. He blinks hard, asks her something, and her answer nearly causes his eyebrows to fly off his head as he slaps a hand over his mouth. She’s nodding at him, and then they’re both grinning and crying at the same time and Theresa throws her arms around Martin’s neck and kisses him hard. He’s whispering something over and over again, hands tangled in her hair, never breaking eye contact, and it’s obvious to anyone that can see them what he’s saying to her.
I’m not really sure about the ending, but it’s 1am and I wanted to have it up before I went to sleep and towards the end it sort of went a bit
So it’s gonna have to do for now
THE ‘PISSY LITTLE LINES’ PART WASN’T AN INTENTIONAL PUN