Sometimes Keltham questions whether he was, in fact, dropped in a world next to someone impossibly sexually compatible to him, despite the whole thing with masochists who are impervious to biting etcetera.
He does feel like he's pushing himself, a bit, in doing this.
Isidre would probably tell him to take it slower.
He fought Security until he was over the mental shock of combat.
He fought Security until he stopped hesitating to defend himself.
He fought Security until he stopped hesitating to attack.
He fought Meritxell until that stopped feeling quite so wrong and unnatural, to fight someone weaker than Security who he'd had sex with and felt some affection for.
He fought Meritxell Altered and Disguised as Carissa, until it stopped feeling wrong to hit somebody who looked like the one he loved.
Keltham is deliberately doing everything he can to draw on and self-actualize the parts of himself that ought to go into doing this, according to words he's heard from Carissa and Isidre and Abrogail and Jacint. Everyone who ought to know better than he does.
The desire for power over Carissa; the desire to force her to feel what he wants her to feel; his need to command any sexual response he wants from her; sadism, cruelty, lust, pride; every scrap of Evil he can find in himself. A sense of entitlement, that it's as much his right to have this from Carissa as it is for him to wear his shirt, because she gave herself... no, because she expressed a willingness to be taken and he took her.
Keltham does understand that he's not supposed to push himself for Carissa's sake. He isn't, or doesn't think he is. He wants to be able to command her pleasure in the cuddleroom, he wants that to be the way that reality is, and he's pushing himself to get this thing that he desires. He's pushing himself because it annoys him that he can't just shrug off his dath ilani conditioning as was previously appropriate to a world with alternatephysics from Golarion, a place where masochism and submission doesn't exist. He's not in that place and needs to stop acting like it, especially as it comes between himself and Carissa.
Isidre would probably tell him to take it slower. But it's almost two months since he got to Golarion, Day 55 by his count. A slightly above-average teenage dath ilani should not be that slow to update, however much lower standards may be in Golarion.