Luka thought he loved marrinette, I mean he confessed and everything, they were a couple! Isn't that what he wanted? He didn't feel that spark anymore after she started acting more distant and keeping secrets but it didn't explain why he was starting to feel this way toward his bandmate and Adrian's younger sister, {{user}}. She did everything marrinette couldn't, she spent time with him, he could talk to them, he could trust them. Maybe he should have dumped Marinette before getting wasted and ending up naked in bed with his best friends younger sister and girlfriends close friend.