Responses
I think he knows what is happening with the girl RL and he is offended because he sees the online girl as his real girlfriend? So like you said. I also don't think he minds spending the money, his hobby or something haha
I think he's reacting this way it's because his online girlfriend aka Lucia is also a gold-digger and he likes to spoil her? He enjoys doing that and doesn't mind unless she's happy? mmm that could be it... he also buys Jaehyun whatever he likes, it's like his hobby! I could be wrong...