Title: Inevitable

Author: A. Windsor

Pairing/Characters: Callie/Arizona, Mark

Rating: PG-13

Disclaimer: All television shows, movies, books, and other copyrighted material referred to in this work, and the characters, settings, and events thereof, are the properties of their respective owners. My one semester of law school could allow me to legalese this a little more, but it also tells me it's pretty useless. So please don't sue; it's not mine, I'm just playing!

Summary: "These are the times when he misses being just best friends, back before what Yang once called his "baby mama, no, baby mamas, drama". When they didn't have to navigate the awkward, uncharted waters of co-parenting in threes and all the inevitable jealousies that come with that. " Companion piece to Easy.

Author's Note: So I said I didn't think there was more for Zeq!verse, but apparently there was. I think this is it, though. It just seized me and needed to be told. There's not a lot of Callie and Arizona together, but it's very Callie/Arizona. (If that makes sense?)

Mark ambushes Callie at the nursing station. Her nose is deep in a chart, but she would recognize his stomping anywhere, so she's not surprised when he starts talking without a greeting.

"So... I just went to the daycare to grab Zeq for lunch and... he's not there."

"Yeah, Arizona got off early today, so they went to the Children's Museum. There's some sort of visiting exhibit about astronomy, I think? I don't know. Whatever it is, they're obsessed. They went Saturday, and she promised him they'd go back. They told me why this one is special, but sometimes when those two go off on a tangent I find it best to nod and smile."

Callie grins fondly, thinking of the way those two ramble excitedly about anything and everything. She looks up from the chart in her hand and sees that her expression is not mirrored.

"What's up?" she questions.

"I had plans to have lunch with him today. It's a little annoying when I go to get him and I don't even know he's left the hospital."

"It's not your day with him, Mark," Callie counters, immediately defensive at Mark's tone. "You don't have to know where he is at any given moment. I forgot you had plans when Arizona told me she was gonna pick him up. I'm sorry."

"I just wanted to have lunch with my kid."

Callie sighs and puts down the chart on the nurse's desk in front of her, smiling politely at the very nosy nurses pretending not to be watching them.

"On-call room. Now."

"That was a lot more fun when it meant something other than getting yelled at," Mark says petulantly.

"Suck it up."

They duck into the nearest on-call room, out of range of the watchful eyes of the hospital's gossip mill.

Mark crosses his arms as Callie locks the door behind them.

"Is this about Arizona taking Ezequiel to the Children's Museum or is this about the fact that he woke up screaming a week ago and wouldn't settle down until you got her to come over?"

Mark clenches his jaw.

"He doesn't mean anything by it, Mark. He loves you; you're his daddy."

"But she makes him feel safe. And I don't, apparently. Because they're attached at the hip, and you do nothing but encourage it."

"Why should I discourage it?"

"You shouldn't; it's great that they're close. But not at the expense of my relationship with my son."

"That's not my problem; your relationship with Zeq is all your own, and I've never done anything to take away from it. I can't mandate that he not want her. She's his mom!"

Mark pulls a face, and Callie puts her hands on her hips.

"Don't you dare say it."

Her voice is laced with pure steel, and he knows that denying that out loud is one line he cannot cross.

"Fine. I won't. But I think you still feel so damn guilty about how Zeq was conceived that you'll give her whatever she wants. I think that you're just so grateful that Robbins wants anything to do with you two, that you'll back her every time. Because you're worried that if you take my side, she'll drop you both in a second."

"This isn't a competition!"

At this point, everyone in the hall can probably hear them, but she's so angry she doesn't care.

"And yes, I back her, because we're partners. Because she's the love of my life. Because we make decisions about him, together. Not because I'm scared of anything. And that's not fair to Arizona. She would never walk away from Zeq, and you know that."

Mark concedes that with a bow of his head as he blows out a frustrated breath. He's usually fine with Arizona's relationship with Zeq, sometimes even grateful for it. Hell, he actually likes Robbins now, probably more than she does him. But as Zeq gets older and can verbally express his preference for his momma, it does sting.

"He's my kid, too."

Callie groans. "Of course he is. I know that."

"Do you?"

Callie's pager interrupts their deadlock and saves him from the death glare that she's currently fixing on him.

"This discussion isn't over, Torres."

Callie grabs the offending device and waves it at him as she unlocks the door. "911. ER."

"We're talking about it tonight," Mark calls after her.

Callie rolls her eyes and gives him a super snarky thumbs up as she heads down the hall.

After his shift, Mark finds the whole little happy family in the attendings lounge as Callie changes. Zeq is standing on the bench, pointing out constellations in a sky only he can see. Arizona sits beside him, shoulder against his hip, arm around his waist, steadying him so that he doesn't fall in his exuberance. Her face is tipped up, trying to make out the shapes he draws.

"Hey, Daddy!" he beams when he notices Mark's presence. He moves to leap from the bench but Arizona stops him.

"Easy, EZ," she laughs. "You have to be careful."

"Sorry, Momma. Can I get down pleeeease? I wanna hug Daddy."

"Well, that is certainly an acceptable reason to get down," Arizona grins as she lets Zeq down.

Mark wonders if the absence of handy bricks means that Callie hasn't told her girlfriend about their earlier argument yet (she will, these two err obnoxiously on the side of overshare these days), or if she is just feigning politeness to lull him into letting his guard down. He and Robbins have come a long way, but she doesn't like it at all when he makes her Calliope upset.

Zeq leaps for him, and he leans down to scoop him up, kissing his sweet little cheek.

"Hey buddy."

"You're scruffy today, Dad. Gotta shave."

"Thanks, Zeq. I forgot."

"You're welcome."

Arizona eyes the tension between Mark and Callie and stands up. Maybe she's been filled in after all. He'll have to be on the look out for bricks when he least expects them.

"Hey, EZ? Mami and Daddy need to talk for a bit. Do you wanna come find Karev with me? I have it on good authority that he has a really awesome toy in his lab coat, and if you ask really nicely, he might even let you hold it."

"Okay, Momma," Zeq agrees happily, squirming to be put down. "What kinda toy is it?"

"Well, that's a surprise," Arizona says, taking Zeq's hand and leading him out the door.

"Bye, Dad. See ya later!"

"Bye, Zeq. I'll see you before you go home."

The door shuts behind them, and they're alone in the lounge. Now fully dressed, Callie crosses her arms over her chest and finally looks at him. When he doesn't say anything, she sighs.

"When he's mad at her, he asks for me."

"What?"

"I'm saying it's not just a you and her thing. He doesn't like her more than he likes you, Mark. Or maybe he does, sometimes, but he doesn't love her more than he loves you. He's four. He says things he doesn't mean all the time, he has the attention span of a gnat, and he usually just wants whoever is not there. When I discipline him, he says he wants Momma, thinking he'll get a reprieve. When she disciplines him, he says he wants me for the same reasons. A lot of the time he tries to convince us that you let him do things we won't. I certainly hope you're not letting him do half the things he says, but I've lost count of how many times I've heard the phrase 'But Daddy would let me'."

Mark opens his mouth to say something, but pauses, processing this.

"And the nightmare thing? They have this little ritual when he wakes up from a bad dream, and I'm not even party to it, and apparently it makes his bad dreams go away. It's just one of their things. Just like when a football game is on he wants to call you, or when certain songs come on the radio he makes you guys text me. So, what I'm saying is: I know that this whole arrangement is hard, and that it's not fair that you only have every other weekend and Wednesdays for dinner. I know that it's not fair that we get him most of the time. And I know that you're still upset that we moved a little further away. But you don't need to take all of that out on me, and you certainly don't need to take it out on Arizona, okay?"

"Okay."

Callie heaves a sigh and narrows her eyes, studying him to make sure he really did take in everything she's said.

"Do you want to take him to dinner?"

"What?"

"You missed lunch, so do you want to take him to dinner now? I'm definitely not gonna object to a little alone time with Arizona if you boys wanna go grab something to eat. And then you can drive him home."

"Yeah, that would be great."

"Okay. Be prepared to hear more than you will ever want to know about galaxies. And no sugar. You only get to hype him up when you're the one who has to deal with bedtime. We've really got enough pep in our house already without adding sugar into the Zeq/Zona equation."

Mark lets out a laugh that drains the rest of the tension from the room.

"I can't believe she lets you call her that."

"She doesn't. Do you see her in the room right now?" Callie teases.

These are the times when he misses being just best friends, back before what Yang once called his "baby mama, no, baby mamas, drama". When they didn't have to navigate the awkward, uncharted waters of co-parenting in threes and all the inevitable jealousies that come with that. Of course, that was before Ezequiel, and Mark wouldn't trade anything in the world for his beautiful son.

"I'm not going to apologize for their relationship," Callie then says quietly, like she might also be flashing back to the days when they were each other's confidantes. These days she saves her innermost thoughts and secrets for Arizona, or if it's about Robbins, for Addison or even Cristina. "And you were sorta right. I am, every day, in awe that she's still here."

"I know. I know their relationship makes you happy, Cal. I know she makes you happy. And I really am happy that you're happy."

Callie takes a deep breath, and he can still read her like a book. She's feeling especially confessional.

"She has a ring."

"What?"

"A ring. In her running shoes. An absolutely stunning diamond solitaire that I found while searching for that Hotwheels car that she got Zeq. You know, that one he won't sleep without. I found it six weeks ago, and who knows how long it's been there. But I don't know why she hasn't used it yet."

"She's probably just waiting for the right moment. It's not romantic to propose over Lucky Charms and a hyperactive toddler."

"You let him eat Lucky Charms?"

"Hey, something's gotta be cool about going to Dad's."

"Dad's cool about going to Dad's."

He smiles appreciatively at the compliment.

She bites her lip. "You really think it's just that? Waiting for the right moment? Not second guessing committing herself to a crazy person with a hyperactive toddler?"

Mark immediately regrets his words from earlier in the day, fueled more by his own frustration than any truth. He really shouldn't use his ability to read her deepest fears for evil just because he's having a rough time.

"Callie. She's already committed. Her name's on the mortgage. She goes to Zeq's parent-teacher conferences, and she put up with sleep deprivation and spit up and infinite poopy diapers. I know she changed more diapers than I did. I mean, she actually likes taking him to the Children's Museum with all those other noisy, snotty brats. And she's stood by you when many a lesser person would've run in terror. When maybe a reasonable person would say she should've run in terror. You said she would never walk away from Zeq, and that's true. But she wouldn't walk away from you, either. She loves you, Callie; she tells me that, all the time, when she yells at me for being a dick."

Callie snorts a little. "She does do that a lot."

"She's got a lot of residual resentment. I get it. But she stayed. Maybe it wasn't her first instinct, but she stayed, and I don't think she's ever regretted the decision."

"You think?"

"I do. Now I am starving, so let's go find Robbins and the little man so we can get dinner and you two can do all those things I'm not allowed to fantasize about anymore."

"Mark..." she warns.

"What? I know what 'alone time' means."

Callie rolls her eyes and punches his shoulder, slipping on her jacket as they go in search of the rest of her family.

They find them harassing Karev on the peds floor, and Zeq's moms agree to walk him to his dad's car. As they get to the front lobby, Zeq exclaims: "I'll race you, Mami!"

"Oh, you're so on," Callie grins back, and the two take off towards the parking lot.

Arizona moves to join them, but Mark grabs her arm and holds her back.

"Use the ring."

Arizona's brow wrinkles, though realization starts to dawn in her eyes.

"Excuse me?"

"She found the ring. So if you're gonna use it, do it soon. Not tonight, but soon. Because knowing you have it but haven't used it yet? That's freaking her out."

"Okay," she nods firmly.

"You gonna use it?"

"Of course I am. I love her, Mark."

"I know. I'm free this weekend if you want me to watch Zeq, even though it's not my weekend. But you'll have to get help with the actual proposal from Altman or Yang or someone. I think me helping you propose crosses all of your precious boundaries."

Arizona laughs. "Yeah, totally does."

"Well. Let me know."

"Okay."

"Okay."

They stare at each other a little awkwardly until Zeq's voice rings out:

"Momma, Daddy, what are you waiting for? I'm hungry!"

fin