I think its because taegun thinks he is attracted to eunseong because of his guiding powers. He thinks that his attraction to eunseong is physiological and not emotional, so he's testing the waters, but he knows that could give eunseong the wrong idea that he likes him back, and taegun fears that by the time they reach that point he won't be able to leave eunseong since he would have let himself depend on him completely, but he also wouldn't want to be in a relationship with him due to his trauma+ thinking he is physically attracted to eunseong only. You need to remember that eunseong is an s rank guide, just being in his presence relaxes you, and that could be mistaken for romantic attraction.
im not exatcly disagreeing with you (just trying to talk), but it’s not a reach to think that someone who was betrayed by their s/o would be scared/stop believing in love, is it? betrayal -> becomes disillusioned with romantic love and relationships -> scared of being hurt again -> starts avoiding love entirely. you could argue that his avoidance is one of the consequences of his trauma, and his core trauma surrounds betrayal/trust. and tbh i’m not sure but i Think that in the beginning taegun was careful and suspicious abt eunsung! so in the current chapters he’s now turning to the next excuse to avoid eunsung/getting hurt, which is the whole spiral abt doubting the permanece of feelings and all that
I agree! I just think that this thought process should be explained better instead of relying on the reader to remember and understand his trauma and infer the whole process of reaching that conclusion.
In the chapter, his trauma was not mentioned at all. While for most people, it's something ever-present that shapes all decisions.
I'm not even asking for much, I would be happy with one additional panel showing his thought process. Maybe even one sentence: "After [the horrible ex], I don't think I can ever truly love again". If we're being fancy, another: "But will that be enough for Eunseong?"
Yes but what exactly would change in a relationship? They are already going on dates, having sex whenever Taegun needs guiding and they are getting along well.
Realistically, the only thing that would change is maybe living together but that's not even a must.
If Taegun really is only worried about this not being enough for Eunseong, then shouldn't he just talk to him and ask?

Ok so I get that Taegun has trauma from that other fucker but why can't he like Eunseong?
His fuckass ex tricked, deceived and used him, so the trauma should be about getting tricked and used again. But Taegun is not scared of that. Instead, the gravity analogy indicates that he's scared of Eunseong getting tired of loving Taegun because Taegun won't love him back.
But why won't Taegun love him back? Why would he reject Eunseong if he asked to date?
Taegun already talks like Eunseong is so important to him, he couldn't live without him but for some reason, he doesn't love him?
This writing just makes Taegun sound like an ass, expecting Eunseong to love him forever without ever being loved back.
Maybe Taegun does not know if he can fall in love again after that asshole of an ex but then his thoughts should be more along the lines of "Can Eunseong keep loving me even if I cannot give him normal love back?"
I hate when authors just slap the trauma label on characters and use that to avoid explaining their character's behavior. Our actions have reasons, even trauma responses do!
It would make so much more sense if Taegun was paranoid about Eunseong only trying to get into his pants, about Eunseong switching up the second they're in an official relationship, paranoid about having missed little red flags, anything. But no, we get nothing. Just "I won't date him" for no reason.
TLDR: Taegun's trauma is not well-written.