"Why do you let her come back?"
Castle stopped in his tracks, brow furrowed in confusion. He turned around to look at Detective Beckett, leaning casually against the side of the apartment building.
"I'm sorry, I don't quite follow."
"Meredith. Your ex-wife." She tucked her hands into her pockets, ambling slowly towards him. "She drives you nuts, I can tell."
The corner of his mouth turned up in a leer. "Like I said…for a crazy person, the sex is fantastic."
Beckett rolled her eyes. "No…I don't think that's it." She eyed him shrewdly.
He shrugged, brushing a stray bit of glass off the shoulder of his coat when he noticed it. "It really is."
"She cheated on you."
"And?" Castle hummed, the jittery adrenaline rush from the shootout earlier mellowing into a strange state of calm.
"Castle, c'mon. Even you can't be that shallow."
He sighed, glancing up at the fire escape above their heads. "She's Alexis' mom. There's always going to be that bond, no matter what we did or said to one another."
"Even though she cheated, even though she left, became an absent mother for Alexis, you still welcome her back?"
"Meredith is the mother of my only child, and the first woman I loved…or thought I did." He tilted his head, chewing his lip in thought. "In hindsight, it does seem a bit like young lust, but…"
She snorted.
Castle grinned absently, rocking back and forth on the balls of his feet. "Meredith and I will always have some sort of bond, through Alexis. She is the mother of my child, she's my first wife, and even though it doesn't exist now, there was originally some love in that." He stared down at the toes of his shoes, suddenly fascinated by the light dusting of shattered glass particles there. "Yeah, I would much rather she stay in LA. Yes, sometimes I freak out a little when I hear she's taken Alexis out somewhere because I'm terrified they'll end up in Paris for lunch again. Yes, my mother absolutely cannot stand her. But Meredith gave me Alexis, and I will forever be grateful for that. I think in return I can tolerate a few visits a year or so."
"Well I never." Beckett tipped her head back, laughing.
"What?"
"Richard Castle is sentimental!"
He shook his head furiously, starting his walk towards the car again. "I am not."
She giggled. "You are too."
Castle shrugged as he continued walking, turning to throw a comment over his shoulder. "If I were sentimental, I wouldn't have used that whole talk to look down your shirt, Detective. Nice purple bra, by the way. So tell me…is that Victoria's Secret, or La Perla?" His eyes twinkled with wicked amusement as he grinned at her, tongue poking between his teeth. "Strictly research, of course."