When Hannibal audaciously asks Jack to tell him about Miriam during their conversation in front of the fire place, of course as is in any conversation involving him, it feeds his ego, but I think Hannibal also genuinely has a (perverse) sort of affection for the people he seems to be friends or lovers with. And in this case he genuinely wanted to know more about her β his captive of so many years β from someone who knows her apart from Hannibal’s influence. And he wanted to know Jack through his perception of her; and understand his regrets.
I think Hannibal cherishes someone’s vulnerabilities as any ordinary person does, only, he doesn’t hesitate to misuse them and ruin the person for them. It doesn’t bring out his mercy, so to speak. He is loving, but rarely ever compassionate. That’s his law. That’s his worldview.