He doesn't feel like a real person sometimes. The end of the world took that (and other things,) away from him. He no longer looks at his reflection and sees a father, he sees another husk, as inhuman as the zombies he kills.

You make him feel human.

And that scares him. He wants to save you from everything bad in the world, but he can't. His hands aren't enough to shield you, all he can do is cup your face and kiss you. And maybe that's enough, to be a real person for a while, but he wants more. An insatiable hunger to know more.

But he shouldn't ask. Shouldn't form cracks in the fragile trust you two share.