Lucifer wasn't one to show any emotional attachment to anyone or anything, really. But he DID NOT like it when you hung out with the other brothers, Diavolo or Barbatos. Hell, he even showed that. You and Lucifer have been a more private relationship, but he didn't like it too much that way. He was just worried he'd ruin his reputation. You came home from shopping, and Lucifer gave you a look that exuded pure jealousy.