I think so too. During the shows, seems like Aff has this bubble around her so it doesn't matter how much attraction Aum has towards her, she's sooo guarded. That's why Aum seems to be openly closer to Joy, when they technically don't have many scenes together in the lakorn at all yet bond quite quickly and well too.
Aum likes outgoing ladies like Pinky. Aum is still young, he wants someone who challenges him. Aff is too serious in person whereas Pinky, she's still young as well, personality compatibility definitely outshines appearances but ahhhhhhh- if only Aff would loosen up a bit offscreen, Aff could turn into a Sunsanee without knowing, robbing Pinky of Aum since Aff is just too lovable!