Agreed. He is nothing like Jihan’s first love. In terms of physical appearance, which most people think they share big similarities, I think the author has just a few styles in drawing characters (you can see it also in Feel My Benefit). Heeseop and Seungbin just happen to have pale skin colour and black hair. That’s why they’re similar in many people’s opinion. If they do share big similarities, Jihan would notice since the first time he met Heeseop, but Jihan didn't seem to care him at all at the first place. And their personalities are completely opposite too, so they don't share any similarities. The reason why Jihan thinks about Seungbin during his interaction with Heeseop is that he’s about to open up to Heeseop and that kind of memories just hold him back from doing so, because he doesn't want to get hurt again. That’s it.
Why ppl said that jihan gave special treatment to heeseop cus he looks like jihan's first love?
I think no... it's because heeseop was different. He's honest and never with women before.
Jihat always left behind for a woman though.
I'll root for heeseop, I love his gap moe from otaku mode to hot guy mode.