Kissing makes her want other things!! This is weird because intellectually she knows that sex is horrible and that the last time he tried to take her clothes off she sort of panicked. Also she's pretty sure they're still not married and therefore they're not really allowed to do anything else anyway. Also it makes her sick, or something, that's probably at all important. It would be a bad idea on all of the levels if they did anything besides kissing.
She has never been frustrated with this before, except about, like, the abstract fact that it might keep her from getting married, but she is kind of very immediately frustrated about it right now? She's not even sure what she wants, except that it definitely involves being touched in some kind of way??
Maybe if she makes enough needy whimpering sounds he'll at least kiss her neck again. That was so nice last time.