Castle, bewildered, watched Kate pace around her living room.

"I don't understand the problem, Kate. Are you glad that he kissed you?"

"What?" Kate stopped, finally, and looked at him. "No! I told you that already. It's just..." She trailed off.

"It's just what, Kate. I admit, I was a little jealous when I saw him kiss you. Okay, more than a little," he admitted when she raised an eyebrow. "But I told you, I understand. I do. So why are we still at odds here?"

Kate sighed, and sat down on the couch next to him. "It made me think, that's all. Not about Vaughn," she said before he could interject. "But just about us. Where are we going? This morning, you chose a videogame over me, for god's sake. Maybe... Ugh. Maybe I'm just worried that our relationship isn't as solid as I thought."

He turned to her. "Kate. About this morning, I told you, I was being a guy, and an idiot. But our relationship? What do you mean? I love you. You know that. And I'm in this for the long haul. It's me who has been waiting for you all these years. Remember?"

He reached for her hand. She took it, squeezed, but then let it go and got to pacing again. "But what now? I feel like things have simmered down with us. Maybe that's normal, but, well, lately I've wondered how invested you really are in this relationship."

Castle shook his head slowly. "I don't understand."

Kate sighed. "Sometimes I feel like I'm doing all the sharing in this relationship."

Castle, who had taken a sip of wine, nearly choked. "What? How do you figure that?"

"Well, Meredith..."

Looking wary, Castle interrupted. "What about Meredith?"

"When Meredith was here, I asked her why things didn't work out between the two of you. She said that you knew everything about her, but that you never really shared anything about yourself with her. And you know what? I think that's true of us, too. You know all about my mother's case, and my father's alcoholism. You know a lot about me. But what do I really know about you? You always joke about the things that bother you. Like that time you made up a story about how you got into writing."

"That wasn't a story. I told you that I paid someone to write a report for me .."

"No, not that. A while back you made up a story about a little boy you knew who was killed at the beach."

"Oh yeah, I remember that," he said with a little smile that faded as he thought about what else she'd said. "But I've shared a lot with you, Kate. More than I've really ever shared with anyone, actually."

"Really Castle? Because I don't see it that way. Meredith..."

Castle held up a hand. "Hold on. Meredith ... I can't believe you would ask Meredith for advice! Anyway, whatever faults we may have had, Meredith and I didn't work out because I walked in on her cheating on me with her director. She and I had been drifting apart by then, yes, mostly because she had little interest in parenting our child and couldn't understand why I didn't want to leave Alexis with a babysitter so we could go clubbing every night. And even if you think that her cheating on me was somehow my fault, I still don't think that Meredith is the person you should turn to for relationship advice."

Kate sat down again. "I'm sorry. I didn't know." She sighed. "But Castle, don't you see? That's just another thing, in fact, a major thing, that you've never shared with me."

"I don't think most men who have been in a relationship for less than a year feel comfortable saying, 'Hey, look at me. I once was married to someone who didn't think I was good enough for her, so she cheated on me.'"

"I'm sorry."

"Kate..."

"No, I'm sorry. I really am. But even if Meredith is a world-class bitch, she still made me think about what we have between us. I can't be the only one who shares in this relationship."

"You aren't. Kate. How can you..." Castle sighed. "Kate. Listen to yourself. You are telling me that you're questioning our relationship based on something my ex-wife said. But that's unfair. I have shared myself with you practically from day one. I have told you about my childhood. You know that my mother was in and out of work, and in and out of relationships, and that I never felt stable. You know that I had nannies, that I spent a lot of my childhood alone in the New York Public library, and that I was in and out of boarding schools. I have told you how lonely I felt in boarding school, how I turned to writing, and how Damian Westlake helped me along. And you were there with me as I struggled with his subsequent fall as my childhood hero. I shared that with you, Kate. I have shared with you the joys and pain of being a single parent to Alexis. I told you how scared I was when she was little and I lost her in the mall. And I have asked for your advice countless times when I was at a loss to help her in her teenage years. You know about my heartbreak with Kyra. You know about my struggles with Jerry Tyson, and you believed in me, you said you did, when he framed me for murder. You know that I believe in fate, and magic. You know that I love you and would do anything for you. Hell, you outright rejected me three times before we got together, but I am still here, Kate. I'm still here because I love you. I believe in you, and I believe in us."

Kate looked taken aback. "Castle, I wasn't thinking. I didn't remember..."

"Wait. Kate, you know enough about me to know that I understand how hard it is to learn to trust somebody. And now, well, I thought we trusted each other. I'm here, where I've wanted to be for so long. But now I'm wondering, Kate. I'm wondering why you would let a comment by Meredith cloud your judgment. And I'm wondering whether you will ever really believe in me."

Castle's phone buzzed at him. He looked at it, and then got up and grabbed his coat.

"Wait, where are you going?"

"That was Alexis. I'm having dinner with her and Max, remember?"

"Oh, yeah." Kate got up. "I'm sorry. We should talk about this more. I do believe in you, you know."

"Do you?"

"Yes." A tear went down Kate's face, and Castle, sighing, reached up to wipe it off with his thumb.

"Kate, I want our relationship to go as far as you'll let it. And I'm willing to share every dirty detail with you, if you'd like. But you can't be so quick to believe the worst, Kate. I don't deserve that. We don't deserve that."

"I love you."

Castle smiled a little, but it didn't quite reach his eyes. "I love you, too. I'll call you later."

They shared a quick kiss, and he left.