Responses
They aren't together and there's a whole chapter dedicated to keane's conflicting feeling on having feelings for 2 people. He doesn't know they're the same person. So it isn't cheating or two timing he trying to get over Onyx who is actively pushing him away to explore a possible relationship with someone he also likes.
Wait if hes clueless about Noct's real identity but still proceeds to kiss him then isnt he basically two timing what an ass