
It's a shame that they didn't translate the chapter into English after the end of the first season, in which the author explained more about Brett and Hayden's personalities. There, for example, it showed the contrasting characteristics between the two, such as Brett being extroverted/Hayden introverted, Brett being more rational/Hayden emotional... and it said that Hayden was very romantic. Until now, Hayden had already shown that he was very attracted to Brett, but he was in denial.
At first Hayden didn't like Brett and accepted the agreement to be sex buddies just for the mutual benefit. But he was never completely happy with it, between chapters 12, 13 and 14 (if I'm not mistaken) there is an internal dialogue in which he condemns himself for it. This was probably due to his romantic personality.
Progressively he becomes more and more attracted to Brett, after all he accepts him as he is and it was with him that he lost his virginity. We must also remember that this is an omegaverse and once the partners are marked, things escalate. Moved by Brett's affection on "honey" night, Hayden discovers that the mark happened out of passion and not a momentary desire. In his brain now Brett is his mate.

i get what you're saying, but even before he remembers that the mark "happened out of passion and not a momentary desire", which happened in chapt 32, hayden is pursuing brett romantically (chapt 29). yeah sure things escalate when partners are bonded, but until hayden realizes how that bond was formed, to his mind it's an unfortunate accident and something to be dealt with away from brett---not something that's making him feel deeper feelings for brett.
im just saying that the shift from "hey i saved you and we're accidentally bonded. let's stay away from each other if our current transactional relationship is going to continue." to "i can't live without you anymore. i am going to make you fall in love with me." is extremely sudden to me. even hayden's desire for a romantic relationship with brett in chapt 29 is confusing to me on a reread, because we spend so much time away from him in the first three chapters of season 2 that it feels like he's developed his feelings off camera. even just a quick scene of him recounting all of his moments with brett and noticing that he's developing feelings for brett would be enough.
frankly, the moment in chapt 32 where hayden remembers how he marked brett because of the sweet moment would work perfectly as his realization that he wants to pursue brett. and indeed, he goes stronger after him after that chapter. but it feels so abrupt because he already wanted that relationship beforehand, and already set boundaries between him and brett because he knew what he wanted and it wasn't to play by brett's transactional game...but suddenly he's deeply in love with brett and will chase after him no matter what??? i don't know man! it just doesn't seem satisfying to me! we were setting up a brett chasing hayden arc! and now it's the opposite! and i feel a bit disappointed...!
anyway sorry for the essay lmfao

i encourage you to re read the story again, there are multiple points that back up hayden’s feelings for brett.
to point out some:
chapter 7: “these days, i sometimes feel more comfortable around him than around other people”.
he spends more time with brett and less time with his friends, he also admits he feels comfortable and we all know it’s because he doesn’t have to hold back. he’s shy around everyone except brett.
chapter 8&9: hayden stops using pheromones suppressants and starts going to the gym, things that are definitely improving his health, as pointed out by his doctor.
basically, brett’s influence on hayden has been positive and even hayden recognizes that and continues to hang out with him.
chapter 10: first time we see hayden tell brett the reason he keeps hanging around him is because he chose to.
let’s be real, in most cases we only stick around people that make us feel good.
chapter 16: the director lady tells hayden to not expect more from brett but hayden has started to get greedier and he wants brett to himself.
it’s natural to want someone’s exclusive attention when no one has made you feel the way they make you feel.
chapter 18: hayden notices brett was hurt. hayden has been paying more attention to brett, when 10 chapters ago could have been unimaginable. even brett tells him “it’s kinda weird seeing you worry about my body”.
again, hayden no longer dislikes brett, if anything, he’s always looking forward to his
messages. brett also calls him out for never initiating contact, which is funny because hayden has taken that to heart and this season he’s the one chasing after brett.
and that’s just to mention some instances but i think you can see now there’s enough evidence.

It's a pretty common trope where one partner has a near-death experience and the other realizes what it would be like to lose them and how much they meant to them, so they become aware of their own feelings/love and resolve to be more open/straightforward about it. Hayden already showed a lot of signs of falling for Brett. I don't think it's necessary to have that melodramatic internal monologue you're describing to ham-fistedly spell it out for the reader even more, especially since we very rarely get to hear the characters' internal thoughts to begin with.

I know! Can’t want to see what happens next because in this chapter, it kinda felt like Brett is done with Hayden now. Like he’s ready to move on from all their situationship. And I thought Hayden was gonna play hard to get until Brett decides to be in an actual relationship with him but now he’s the one chasing?

i agree with you, i noticed all of those signs too (and even wrote about them on a list a while ago: "...it's not often that seeing the characters of a bl visibly look like they're falling in love makes me giggle and kick my feet up. but it is the case here. their relationship was at first just sexual and transactional, but Hayden staring longingly after Brett as he leaves, or Brett kissing Hayden on the cheek so tenderly, is just..."). i just hoped that the 'falling in love' portion would take more time, as i assumed, based on my personal reading and conceptions of the story, that both hayden and brett were, to some extent, emotionally repressed. hayden because of his trauma with the omega he hurt, brett because of his upbringing. certainly hayden becomes less repressed as the story goes on, i just personally hoped that that journey would've continued for a little longer before he came to terms with his feelings for brett! and thats my burden to bear lmfao

true, but i still personally would've liked to witness hayden's mindset change after his near-death experience by even just getting a quick glimpse---or even one or two panels, no dialogue--of him by himself thinking it over at the hospital (as the first and i believe only times we see him there is when brett is there, and hayden's already realized his feelings). as i said i love that we do rarely hear internal monologues in this manhwa, but it still happens, and imo i thought that this would've been one of best times to use it

ok i think i get you better now. it seems this story won’t be a long one so the author has to carefully place each scene to use as reference in later scenes, hence why there are not many “filler” moments. that’s how the story has progressed so far: something happens, we don’t know their pov, later on we see a flashback of them and their thoughts of that moment.
it would be nice to have more insight of their true feelings but maybe that’ll happen once the story ends, in side stories. but we have to wait and see.
i just read the latest official upload (34) and i never thought i'd be saying this, and pls don't crucify me i still hold this manhwa dear to my heart, but i just don't get why hayden is suddenly head over heels for brett. like i totally understand hayden feeling fond for brett, esp because he helps him during his ruts and encourages him to not hide himself for the benefit of other people...but, like, genuine love? him saying "i can't be without you anymore" and it being framed as romantic and real? uhhhhhhh. okieeee. im just not clicking with these romantic confessions. idk.
i was able to ignore it up until now because i thought it was going to be a thing where we see the two of them grow closer and mutually become more attached to each other, but instead it's hayden being in love and chasing brett. which is fine, that's totally fine and a valid story maneuver, but it strikes me as a bit contrived considering hayden was at most crushing in the first season. like blushing here or there.
sure, hayden protecting brett from the bullet at the end of season 1 was evidence of him feeling something stronger, but i personally, in my own interpretation, thought it was going to lead to harder introspection by hayden. why did i risk my life to save brett's? why was that my instinct? do i feel deeper about him than i realize? etc etc. sort of an internal crisis, if you will. but instead we get to season 2 and he's already made up his mind that he's going to pursue brett and is in love with him. well. ok. a bit of insight into that transition could've been nice...i've always loved how this manhwa is very cinematic in that it uses very little internal monologue (among other aspects), but just this once we could've done with some of that
idk. i still love this manhwa dearly (once again please don't send me to the shadow realm), but i'm kinda disappointed in how their relationship is shaking up. still hoping for the best, and i hope i change my mind in the chapters to come!!