Hades knew that this place was enough to take in, so he hadn't wanted to add more to her plate...but he also hadn't wanted to lie to her. He wanted to share what was going on his life, and more importantly make sure that she knew there were other good people here. Not that he ever thought of himself as good....no he just wasn't truly evil anymore. Mostly because of Mal, but he also found himself wanting to walk a different path as of late because of Maria. Yes his idea for taking power away from his brother hadn't been his best idea, but in his defense he had been blinded by eons of hatred for the man who had basically sentenced him to a life of hell. Hades had accepted his role now though, and ever since Mal had welcomed him off the isle he had found himself leaning towards a more even tempered life.
He also knew that a big reason Maria had gotten passed his walls so quickly was because Mal had already broke some of them down. "It certainly is...but I am pleased you are here with me" he admitted, wanting her to know that she was still a huge part of his life. "I couldn't imagine not having you in my life now. I wasted so much time being stubborn and convincing myself that not getting along with your mom meant I had to cut you out as well" he added. "But you know all of this already...." he added, not wanting to bore her with details of the past.