By calling Binx unreligious and self-centered, Kate means that she sees Binx as a sort of God-like figure: by virtue of his search, he stands apart from the world (he doesn’t feel bound by conventional expectations of any kind). Because of that stance, Kate finds him to be an ideal husband for her—he can be trusted to tell her what to do in life, untainted by self-interest. Agreed on this, they try to become sexually intimate, but it proves too difficult for them both. This suggests, in part, that real emotional intimacy is a new experience for Binx, dampening his usual lust towards women.