[Disclaimer: Don't own the characters or the show. Never will and not trying to claim them.]
She's different than he expected she'd be here. Now, like this. He expected her to be more like the Detective Beckett he's used to—vocal, and take-charge, and maybe even a little bit no-nonsense about things. But this first time is totally different than all of the many ways he's imagined it, and he realizes that it is because he only really knew the Detective Beckett side of her. He's seen glimpses of Kate—of the woman she is deep down and regardless of her career and her past and whatever those fears are that he still sees clinging to the edges of her—but this is the first time he's really been given an opportunity to know her—to understand her, care for her.
To love her.
Kate is shy. She's sensitive, physically. Emotionally too, but that part he'd recognized already. She responds to quiet presence and gentle touch. He realized by the time she led him back to his room that Kate couldn't quite handle hard and fast—at least not yet. She's more fragile than she really wants to admit. It's evident in the way her eyes go wide at his touch. He is careful to pay attention: to learn in a single night how to understand what she likes, what she wants, and what makes her feel safe. She responds better the gentler he is.
She is not at all a vocal lover, which comes as a surprise to him. She uses no words, makes only the quietest of sounds—barely audible moans and breathy sighs. He's surprised when, after their first round, he's yet to hear her voice at all. Of course he knows that she struggles with communication, but it's something he never expected to translate into lovemaking. In the stillness of after, she silently shakes her head at the whispered request of "Kate, please say something to me." She unfolds herself from his side, kisses the edge of his mouth softly before meeting his eyes. Swept up as he is in her, he easily contents himself with her fervent nod—and if he's not mistaken a faint and breathy 'yes'—when asked if this is truly what she wants, for tonight and for them.
It takes two rounds to understand that any roughness at all only makes Kate shut down. Detective Beckett, he always imagined, would be most interested in rough and fast and hard and probably without a lot of thought. Kate, though, deals in intimacy. At first, she is hesitant to touch. She'll be touched, but she seems almost fearful to touch in return. She brushes her fingers softly, carefully over his face, through his hair. It's not until after that first time that she finally, finally overcomes the shyness and the hesitancy.
More than once he catches himself beginning to take things too fast, realizes that he's in some way losing her. It's as he slows down, gentles his touch, that he feels her unfurl. Feels her relax and begin again to make those soft satisfied sounds he already loves—already longs to coax from that best-protected and most sensitive part of her heart: the part, he suddenly realizes, that really and truly wants him.
It takes three rounds to realize that she needs to be talked through—just a little bit. A word here, a few seconds of eye contact there; it all makes a big difference. Suddenly he finds Kate more open to him, more relaxed and more herself. He thinks perhaps that she's simply more used to him—to them—after a little time; thinks that maybe all she needed was to adjust to this change in their relationship. But when, experimentally, he moves his hands lower without saying a word, he feels her tense beneath him. He pauses then to reassure her both with words and with his mouth moving against hers. Instantly he feels her body relax into his touch. So she likes the added bit of surety received through his words.
It's the afterglow that makes him fall in love with her all over again. It's then that he realizes how deeply affectionate Kate is. She's quieter than she has been all night, but she clings, warm and soft and sated next to him. He watches and caresses as she drifts in and out of sleep until finally succumbing for the night, hears her murmur his name sleepily just before. He soothes her when once she wakes suddenly, startled by their intimate proximity. He watches as the realization, the recognition seeps in and her expression melts into one of trust and tranquility and love. He feels her tuck herself a little more closely into his side before she gradually drifts back to sleep in his arms. And he swears he must be dreaming.