Six months later

Derek makes his way to the Hamptons house, he smiles brightly as he carries a gift box.

He's never been happier to be on that beach than he is now, celebrating his son's birthday is still something surreal for him.

The last six months have been amazing, Derek has been able to travel to New York every month and enjoy every moment with Chris. Their relationship is now even stronger and the baby is totally attached to him.

With Addison, things were totally different. The first time he came back after New Year's she'd set rules, Derek was supposed to pick Chris up on Fridays and deliver on Sundays, so he'd take the baby to Connecticut, or Liz's house and she'd spend that time with Pete. Contact between the two became minimal and there were weekends when he didn't even see her.

Meanwhile, back in Seattle, things with Meredith have continued to be a bit awkward, she still doesn't want to meet Chris and keeps aloof in any conversation about the child.

All of these reasons only make Derek more excited about his son's birthday, being in the Hamptons a day early is the best way to get closer to his ex-wife and undo the awkward atmosphere she's set.

Derek slams the door with a bright smile, which disappears as soon as it is opened by Pete. The two men stare at each other in awkward silence for a few moments until Addison's boyfriend asks:

"You here today?"

"I came to help prepare my son's birthday. Can I come in?"

Derek speaks in his smug tone and Pete just nods, giving him room to enter.

As soon as he enters the room, he is hit by a whirlwind of memories of the best times spent there with Addison.

Soon, Derek composes himself and asks with a nostalgic smile:

"Where are they?"

"Addison is bathing him."

Derek nods and looks around the room, before commenting:

"Addie told me you'd be on duty today."

"Yes, but I switched with a colleague. I didn't want to be tired for Chris' birthday tomorrow."

Derek nods again and shifts the box he's carrying, as he feels it move. At that moment, Addison appears with Chris clinging to her neck, already wearing pajamas. As soon as she sees his father, the little boy lets go of his mother's neck who puts him on the floor, he runs into Derek's arms.

Derek immediately gets on his knees and puts the gift box on the floor, he takes his son in his arms and holds him tightly while whispering:

"Happy birthday my love. Daddy is so happy to be able to be here with you."

Chris then walks away and proudly states demonstrating with his little fingers:

"It's been two, Daddy."

Derek smiles proudly too. Addison asks with furrowed brows:

"Derek, why is your box moving?"

Just then he remembers the gift, he laughs and pulls the box close, putting his son on the floor as he says:

"I brought you a special gift, Chris."

"Which?"

"Let's open."

Derek talks excitedly and begins to untie the red bow on the box, from which a small yellow lab puppy emerges. Chris' eyes shine at this moment and he holds the animal in his little hands while yelling:

"A whoa whoa, Mom."

Addison approaches with arms crossed asking with a raised eyebrow:

"A dog, Derek, really?"

"Look at his happiness, Addie."

Derek speaks with a goofy smile, but Addison still looks annoyed. He then justifies himself:

"Growing up with a dog helps children's development."

"Derek, a dog is going to be a lot of work."

"But it will make Chris happy. Mom never wanted to give us a dog growing up."

"Your mother had five children, the last thing she needed was a dog."

"You only have Chris, so there's room for a dog."

Derek speaks with a crooked smile. Addison can't help but smile and then her gazes meet in comfortable silence.

Pete notices the exchange of knowing glances between his girlfriend and the neurosurgeon, immediately questioning:

"And what are we going to do while we're here? A dog needs a lot of things."

"I have everything in the car."

Derek speaks simply and strokes his son's hair as he continues to clap and pet his new dog. After another silence and noticing Pete's uncomfortable posture, Derek says:

"Addie, you said Peter would be on duty today. I didn't want to disturb you. I think I'd better find a hotel."

"Imagine Derek. You came to help and you're already here. You can stay in guest rooms for a day."

Addison speaks matter-of-factly before continuing:

"Even you guys stay here with Chris and I'll prepare the room."

After that she turns around and goes up the stairs again. Derek decides to go to the car to get his suitcase and the puppy's stuff, while Pete sits on the mat with Chris.

Soon Derek comes back with things and the scene in front of him hurts more than he would like, Pete is sitting on the floor with Chris, they both laugh and play with the puppy. As soon as he sees his father again, the little boy gets up and jumps towards him, saying excitedly:

"Dad not though."

"No buddy. Daddy just went to get the au au things."

Chris nods happily and starts trying to catch the dog's leash. Soon Pete gets up from the floor and offers to help Derek organize the animal in the laundry area.

When Addison comes back, Derek is walking with Chris on his shoulders, while the little boy laughs and waves his arms. Addison smiles at both of them before asking:

"And the dog?"

"Peter is organizing his stuff, this little guy here won't let me help."

"This little guy needs sleep."

"Let me put him to bed."

"Thanks."

Addison talks approaching, she gently caresses Derek's arm, leans in to kiss her son's cheek and then heads towards the kitchen.

Derek takes Chris on his lap and carries him upstairs to his room, promising to tell him a story.

AAAAAAA

Half na hour later, Derek goes back downstairs and finds no one. He walks to the kitchen, where he finds Pete preparing dinner, even embarrassed he asks for Addison to which the other man replies being in the pool.

Derek walks out of the house and finds his ex-wife sitting on a lounge chair, drinking a glass of wine and watching the pool. Derek smiles, once again flooded with many memories of summer nights spent there, of having Addison so relaxed and casual, waiting for him to make dinner. He watches her for several minutes until he hears her voice ask:

"Are you okay?"

Derek then comes out of his reverie and finds her still sitting up, but now facing him and frowning. He smiles nodding and approaches saying:

"Too many memories..."

Addison nods and looks away at the water again. Derek sits on the lounge chair next to him and reaches for his wine glass, Addison hands it to him and he takes a sip before speaking:

"I never imagined being here again."

"I never imagined seeing you here."

"I wanted to surprise you, spend some time with you."

"Derek..."

"We haven't had a decent conversation in months, Addie."

"We don't have anything to talk about. Chris is fine, we have a system that works."

"We kissed three times and then you shut me up."

"Because it was lapses in judgment. We're both divorced and engaged to other people."

"And you think I don't know that?!"

Derek asks raising his tone. Addison gives him a dirty look and he takes a deep breath before continuing to speak, this time lower:

"You think I haven't spent the last six months blaming myself for keeping this from Meredith?!"

"It's all the more reason to stay away."

"It's just that you pushing me away like that, it hurts."

Derek speaks in a vulnerable tone, surprising them both. Addison's gaze softens, but before she can say anything, Pete appears, telling her that dinner is ready.

Addison nods and stands up, turning her back on Derek and walking into the house.

Derek gets up, puts both hands in his pockets and approaches the pool, he takes a few deep breaths and then goes back to the house too.

As Derek walks past the kitchen, Addison gently asks:

"Aren't you going to dinner?"

"No. I ate before I came here and I'm tired. Have a good night."

"Goodnight."

Addison and Pete respond in unison as they watch the neurosurgeon walk away.

AAAAAAA

The day starts early with the arrival of the party decoration team. While Pete and Addison help with the details, Derek stays with his son.

He helps him interact with the dog he starts calling Fop and ends up becoming the little pup's official name.

The hours go by like this, until a little after lunchtime, Amelia arrives.

Derek opens the door for her with Chris in his arms and as soon as he sees her the little boy yells his nickname. Amelia quickly pulls her godson into her arms as she enters the house asking:

"What are you doing here?"

"I arrived yesterday, I came to help Addie."

"Did you spend the night here with Addie and Pete?"

Amelia asks with furrowed brows causing Derek to look away. She sits down and starts playing with Chris as she helps him open his present.

It is at this moment that Addison appears, she smiles brightly at her friend, but says in surprise:

"You are early."

"I came to help, but it looks like you're already in good company."

She speaks maliciously and gets a dirty look from Derek. Addison decides to ignore the comment and says smiling:

"I appreciate it. If you can get Chris ready while I do. Everyone should be arriving soon."

Amelia nods and the two go up the stairs together with the boy.

AAAA

Less than two hours later, everyone is ready and begins to receive guests. First to arrive are Savvy and Weiss with their adorable kids, then a few of Addison's friends, Archer, and finally Derek's other three sisters with all their husbands, kids, and of course Carolyn.

Everything goes well, until Weiss needs to get away from Derek to attend to one of the children, which is when Amelia sits next to her older brother. She looks at him with raised eyebrows for a moment and asks:

"Why did you come to the Hamptons?"

"For my son's birthday."

"If that was why you would have arrived today like everyone else."

"His birthday was yesterday."

Derek talks trying to end the matter, but Amelia just rolls her eyes. Then she asks:

"You wanted to spend time alone with Addie, didn't you?"

"We weren't alone, Peter was here."

Derek speaks and his tone doesn't go unnoticed by Amelia. She glances in Addison's direction and Derek does the same, not that he hasn't looked at her for most of the party. She looks gorgeous in her aqua green dress that goes down to her knees, her hair down in soft waves and light makeup. After a few seconds Amelia speaks again:

"How are things between you and your girlfriend?"

"Amy..."

"It's just a question."

Amelia speaks with mock honesty and Derek sighs in defeat deciding to be honest. Once upon a time he might have vented to Mark, or Weiss, but the former was totally out of the question, while the lawyer would likely tell Savvy. So Derek realizes that his younger sister will be his best option:

"We kissed three times when I first met Chris and after that she shut me up."

"The Addie?!"

Amelia asks in a louder tone than she should and gets a frown from Derek. She then whispers:

"I can't believe she didn't tell me about it."

"Must be because it didn't mean anything to her."

"It's for you?"

"It was the realest thing that's happened to me in years. It felt right and at home…every time."

Derek speaks with a sincerity that surprises him. Amelia is shocked for a moment, but then speaks in the lowest voice she can manage:

"Derek, you are my brother and one of the people I love the most in the world. So I have to tell you, don't let that feeling pass. Pete is a really nice guy, na admirable doctor and he's really good with Addison and Chris, but he's not you, he's never going to be you to her. Nobody will."

"But he's the one she's with."

"Because she's hurt and because she sure as hell has no idea how you feel."

Amelia speaks and Derek lowers his eyes, she holds his hand and says:

"I know she hurt you a lot, that what she did was horrible, but I know you've forgiven him, just like she forgave you for Seattle. Only those who have seen you together know what it was like and what it meant."

"Amy, let it go."

"No. You've got a family over there Derek, a wife who still loves you, and a beautiful son. Enough of this character who lives in Seattle, dates a girl nobody knows, and lives in a trailer. Nobody throws a third of their lives away that easily."

Derek stares at his sister speechless for a few moments before speaking with a smile:

"When did you get so mature, Amelia Shepherd?"

"I am learning."

Amelia speaks with a smile and then stands up stating:

"Now I'm going to get my godson out of Kathleen's clutches before she traumatizes him."

She winks at Derek and walks away towards her older sister.

Derek smiles watching her and then turns his gaze to Addison. She is smiling surrounded by her friends as she listens to some funny story from Savvy, so her eyes meet for a few moments, he smiles at her and she returns it. And in that moment he knows Amelia is right. She is his Addie, the woman he has loved since he was 22, the woman who has been his companion, his supporter and his inspiration, she is his and he is hers.

The party continues and then it's time to sing happy birthday to Chris. Everyone gathers in front of the boy who is on Addison's lap and then asks, extending his arms:

"Daddy! Daddy!"

Derek smiles and approaches a little awkwardly, he stands next to Addison and strokes his son's back. For a moment between smiles and applause, they are family again.

AAAAAAAAA

When everyone starts to leave, Derek looks for his mother to say goodbye, he carries Chris inside the house. Derek stops outside listening to Addison and Carolyn's voices:

"Chris looks so much like Derek when he was that age."

"I know. I hope he grows up to be as amazing a man as his father."

"He will. You're doing a great job, Addie."

Derek smiles, he can't see his ex-wife's expression, but he knows how much those words mean to her. During their years of marriage, Carolyn had always charged grandchildren, but Addison was never ready and he knew why. Having been raised by Bizzy she feared not being a good mother and compared herself to the mother-in-law she always sought approval from. It seems ironic to Derek that the approval came after the divorce.

When he notices that the conversation has become less serious, he finally enters the house talking excitedly:

"We came to say goodbye, grandma!"

Chris then asks to get off his father's lap and runs to his grandmother's waist, who quickly lifts him up. She kisses the boy's cheek before hugging her son. Soon Nancy appears with the family, everyone says goodbye and Derek escorts them to the car.

When he comes back inside the house, Addison is sitting on the couch, drinking a glass of champagne, Derek sits with his son on his lap and says:

"It was a great day."

"Yes, it was. Do you accept?"

She asks pointing to the drink, but Derek refuses:

"No. I'll be driving in a little while. My flight leaves early tomorrow."

"Your mom says I'm doing a good job with Chris."

She speaks with a beaming smile. Derek also smiles and states:

"It is. But I never doubted that."

Addison smiles even wider and they stare at each other for a moment. On impulse, Derek asks:

"Can we take Chris for a walk on the beach before I go?"

"Don't you think he's too tired for that?"

"It's just a ride."

He asks with his mcdreamy look and Addison sighs nodding. She finishes her glass, goes to the pool where Pete is packing up, and informs him of her plans.

Soon Addison returns and the three of them leave together.

AAAAA

They walk across the sand, each holding a small hand from Chris. The sun is starting to go down and the wind is light and relaxing. Chris gets distracted by every different thing he sees in the sand and gets his parents' undivided attention. Suddenly Derek surprises his ex:

"We need to talk about us."

"Derek, there's no us."

"There will always be us. We are AddisonandDerek."

"It was us, today we are na ex-couple who have been hurt enough to last a lifetime."

"Addie..."

"Derek, I don't want to do this anymore. For Chris's sake we have to live without this elephant in the middle of the room and the only way is if you stop. I've got Pete, you've got Meredith, we've made these choices and we can't come back."

"I didn't make that choice. I didn't sign the divorce papers the first time and I said I didn't want to leave you."

"You made that choice the moment you walked out the door of our house when I warned you that we wouldn't survive if you didn't stay."

Her words cut deep and her eyes are hard, so hard Derek has to look away. Addison takes a deep breath and says:

"Let's stop talking about it. Let's focus on the amazing son we have and not this past that only hurts more."

In that moment her eyes are vulnerable and bring tears to Derek's. He just nods and opts for silence, leading her and her son out to sea.

Chris screams excitedly and scared as his little feet hit the cold water, making the parents smile. They hold tightly to the hands of their son who, in a few moments, gets used to the sea and screams excitedly with each wave that hits his feet.

Derek and Addison smile looking at the little redhead and then at each other, in this moment they are happy.

AAAAAA

I appreciate and appreciate your comments.