The lack of reaction is telling, given that Steve at least understands now that absolutely everything can be listened to, and likely seen. He has no doubt that means that Asmodeus is either choosing to ignore, or the threat itself is meaningless.

He also doesn't doubt that Zerxus is reeling, emotionally. Maybe he should leave it alone, but.

"Is he? Or is he using other people to hurt you?" He can't speak to Evandrin, and that bit of information makes him hurt more for Zerxus, but the fact remains: "He doesn't care about me enough to want to hurt me. He certainly didn't before I showed up here, anyway. You...."

He's walking around wearing your husband's face.