Kissing someone can be remarkably shallow and unintimate - for some people it's only bodies, after all, even if Seth usually attaches a bit more significance to it. But probing into someone's past, into their feelings and motivations and experiences, that's asking someone about who they are, about things that make them them.

As it is, Seth's question isn't inherently that personal and soul-probing, just potentially, and perhaps a little awkward. "How many people have you, you know, been with?"