He had been looking for something specific. When he discovered the extent of the role she played in finding and destroying his horcruxes, he hadn't been angry. No, if anything, he'd been impressed. His conceit and arrogance meant that he had not even been capable of believing for a second that anyone would learn his secret. It might have been infuriating to learn that he wasn't as secure as he thought, but he wasn't going to let the opportunity to find out more slip through his spider-like fingers just because his followers were clamoring for her blood.