Beckett gets proposed to which leads her to an interesting realisation as she imagines married life. What does Castle have to do with it?

Set towards the end of season 3 and sort of AU. I hope you enjoy it.

The next chapter of Seeing Double will be posted in the next few days.

Disclaimer: I don't own Castle or the characters.

She hadn't seen it coming. One minute they were talking and next he was down on one knee.

"Will you marry me?"

Beckett didn't know how to respond. She just stood there, looking at the man in front of her down on one knee. So she started to imagine, to imagine what her life would be like if she got married.

She would be waking up next to the same person for the rest of her life. He'd be the one she came home to at night after a tough day at work. Someone who would comfort her, look after her, protect her.

And later on, maybe they'd have kids. They'd be woken at 3 o'clock in the morning to a crying baby but even though they'd be sleep deprived, one of them would get up to feed their son or daughter and she'd see that smile on his face, the one he reserves just for his kids and she couldn't imagine a better life. And a few years later, when she's pregnant with their second child and she'd be sitting on the couch watching her child and husband chase each other around the living room. He'd scoop up the kid and spin him or her around and soon they'd all be smiling and laughing and they'd be happy.

Her mind wandered and she started to think about what their wedding day would be like. She'd be dressed in a beautiful white dress and her father would walk her down the aisle with her friends smiling at her as she walked past them. She'd look up and see that stupid grin on her future husbands face and would know that she'd made the right decision. By the time she reached the altar she'd be wearing a grin to match his and it would take all her self control not to just reach out and kiss him then. Once the priest declared that they could kiss, she'd kiss him, their first kiss as husband and wife, and she wouldn't want to let go of him ever again.

Beckett must have zoned out because she was bought back to the present when she heard a throat being cleared. She looked down and realised she hadn't given her answer yet but she already knew what it was going to be.

"I'm sorry, I can't," she replied, feeling guilty about saying no but knowing all along that this relationship was going nowhere.

She knew that she had to say no because the person she'd been imagining spending the rest of her life with was Castle, but that wasn't who was kneeling in front of her now.

Josh told Kate that deep down, he always knew that they wouldn't work out. While he did love her and wanted to spend the rest of his life with her, he could tell her heart wasn't in it. It was his last desperate attempt to win her over and while he'd hoped she'd say yes, he knew she wouldn't. It wasn't long before he'd grabbed his few belongings that had been at her place and then left.

Beckett didn't know why it had taken her so long to break it off with Josh. She felt bad stringing him along for so long when she knew it was going nowhere. She'd been hiding in a relationship with him because she's been scared about the possibility of being with Castle, she didn't want to break them. But she didn't want to wait any longer, she wanted to tell Castle exactly how she felt and she hoped that he felt the same way about her too.

XoXoX

Half an hour later she was standing outside his door. On the way over she'd been trying to figure out exactly what she'd say but she couldn't seem to find the right words. Hopefully she'd be able to articulate her thoughts when she saw him. She had to tell Castle what she's just realized, she can't wait any longer.

It didn't take him long to answer the door after she'd knocked.

Castle was confused when he saw a grinning Kate Beckett on his doorstep.

"Kate?" he questioned, when she just stood there staring at him, still with the huge smile on her face.

"Josh proposed," she blurted out. That wasn't what she'd been meaning to say and she knew it was the wrong thing to say when she saw the hurt expression flash across his face.

"Congratulations," Castle replied, his voice and face void of any emotion. She looked happy and that was what mattered but right now, Castle couldn't face the fact that he'd waited too long and would never get his chance with her, "but if you don't mind I have work to do so I'll see you at the precinct tomorrow".

He tried to shut the door but Beckett pushed her way through the door and into the loft.

"Wait, that came out wrong," she said, knowing that she was going about this whole conversation in the wrong way.

"It seemed pretty clear to me," replied Castle, and Beckett's heart was breaking at the look if sadness he couldn't quite conceal in his eyes. But then the look in his eyes changed, to one of determination.

"Fine," he continued, "if you won't leave then there is something that you need to hear since it's probably the last chance I have to say it."

"Castle, what are you tal-" she tried to say but Castle cut her off.

"Kate, please, I need to say this," said Castle, and Beckett just stood there, eyes telling him to continue.

"All I've ever wanted for you is to be happy, and if Josh makes you happy then I'll have to accept that," Castle could tell Beckett was going to interrupt again so Castle held up his hand, begging her with his eyes to let him continue, "but I have to tell you something. I love you and I have for some time now. I always thought we'd have our chance together but the time was never right. And now Josh has proposed and I've missed my chance and that is one of the things I'm going to regret for the rest of my life." He'd finally said the words to her and at least he can say he told her. Now he just wanted to leave so he could start at least trying to get over her.

"Castle, I said no," Beckett firmly stated, when she'd gotten over the shock of what Castle had just said.

"What?" he asked, now confused. Why would Beckett look so happy if she'd turned Josh down?

"I said no," she stated again, "Josh and I broke up."

"I...I don't understand," Castle replied. Now he was seriously confused.

"I'm sorry, maybe I shouldn't have started with "Josh proposed", but I panicked," Beckett replied, shrugging her shoulders sheepishly.

"You panicked?" Castle asked, he really wasn't following this conversation at all now.

"Okay, let me explain," Beckett started, before taking a deep breath to begin her explanation, "Josh proposed, and I said no, but not before I started to imagine what married life would be like, what spending the rest of my life with one the same person would be like".

Castle still looked confused and he was about to interrupt when Beckett held up her hand.

"Hold on, I've got to get this out, you have to know," she continued. "He was down on one knee and there I was thinking about the future. About late night dinners and waking up beside the same person every day and about starting a family. And then I started thinking about the wedding. Walking down the aisle and being surrounded by friends and family. I looked up and everyone was there, my dad, Lanie, Ryan and Esposito and of course, there was you."

"Look Beckett, I really don't want to hear this," said Castle, not understanding what Beckett was trying to say. Why would she be imagining getting married to Josh if she'd turned him down?

"Just let me finish, Castle," Beckett pleaded, and when Castle said nothing more she continued, "but you weren't in the crowd with the rest of them, you were standing at the altar grinning like an idiot as I walked towards you".

Beckett couldn't stop the tears from falling from her eyes as she kept talking, "And it wasn't just then, all of it was you. You were the one I'd see every night before I'd close my eyes, the one who'd be holding our crying baby at 3am. You're the only person I can imagine spending the rest of my life with."

She couldn't believe she'd just said all that and now she noticed tears threatening to spill from Castle's eyes and before she knew what was happening, he was moving forward and captured her lips in kiss.

He pulled back shortly after and spoke, "Are you sure this is what you want? Because once you're mine I'm never going to let you go." And the intense look in Castle's eyes told her that he was telling the truth.

"I've never been so sure of anything in my life," said Beckett, as she captured Castle's lips in another kiss.

Thanks for reading and please let me know what you thought :)