Well it's more about the person who gave him the toys though. Jiwon is also under the impression, and rightly so that DG wants "Alex" who is basically as fake as that plastic toy too. Hence why he plays a part, even putting back on that mask in later chapters. We know why DG acts the way he does, but Jiwon's personality and reluctance to let go of not being authentic hasn't really been explored yet. Someone else already has pointed out that as well as the Alex role, he also puts on a mask of politeness at university too. Maybe the real Jiwon is the guy who likes to drown his sorrows in a bottle of wine and read all the gossip about him and his work mates online, as seen in a previous chapter.
Woow jealous of the sex toys too!!! He's got it bad