You mean Hera, surely. That was the price of not having finished the Labors yet; he refers to his moment of play with Ares' hired hooker as "respite" from the "burning" of the madness, which makes it seem more like a physical or stress thing than literal, sanity-inhibiting madness.
Don't know why Perez mentions it at all, really; "Hera's madness" should refer to the momentary insanity that caused him to kill his family, and that was long over when he was doing the Labors, since the whole point of doing the Labors was to atone for what he did under the influence of the madness.