magnum

I'm fully convinced at this point that the throw up scene was in fact a red herring and was obviously thrown in at that timing to confuse us. Upon rereading with the additional context, I think it's possible it was a way to show that Guwon was likely dealing with the same bug the little kid got. As we know, adult colds can be rough even for us, but that same bug for a little kid with no medicine can be quite fatal. Supporting evidence; He mentions not being able to provide teach with meds and for him not to feel too bad, because that same rule applies to him even when he's sick. He also mentions he hasn't been feeling well, tired, etc.

The comment where he's praising himself-- I think he was just earnestly doing so, not maliciously. I don't think he was trying to imply he was manipulating teach with his looks. I think he was just literally off handedly saying "Damn, I'm sexy". He has a habit of doing so from the first few times we see him, when he gives teach shoes. I think it's a habit.

Unrelated to the throw up scene, I'm more worried that them swapping blood will prove to be a bigger deal down the line

I'll do the broad strokes below, but if you were too impatient and curious like me, I'd recommend supporting the official release. Digital chapters are like 150 yen which is about 1 dollar, and there's only 3 chapter's beyond what is available here, which is very little money. If you can't read Japanese, you can use IsManga's chrome extension to get general translations that serve their purpose (I recommend zooming in and out of the viewer when you read the chapters if the translation is not working, this usually forces the app to translate it the page that isn't translating). I already own all the released Japanese volumes and am waiting for the 3rd that is coming in May, so my conscience is clear: https://renta.papy.co.jp/renta/sc/frm/item/287661/title/2640514/

Spoilerfied Summary:
Hitomi and Kamiya go to the doctor to check up on Hitomi's recently developed theriomorphosis and they get the condition confirmed, though his expression is likely to be different that Kamiya's, since he only had the psuedogene. While at the doctor, Kamiya expresses his concern about Hitomi's pheromones and how a simply look from him will cause them to leak out, which he promptly demonstrates. He says this is contributing to his uneasiness, because he doesn't want others to smell it. Obviously the doctor can't verify, so he enlists the help of another Beastman (a Lion named Shishino), who appears to be another patient of his. Shishino smells Hitomi at a distance thinking that he is not likely to be able to smell a person he just met, but as he's thinking that, smells a faint, oppressive smell. Kamiya goes into overprotective mode out of instinct as Shishino attempts to smell Hitomi a bit more, which makes the lion realize it's KAMIYA's pheromones that are coming off of Hitomi. He smells Kamiya some more, to which he's about to object, only for Shishino to show his wedding band and assure them that he is not interested.

The doctor is about to suggest they all make a LINE chat (the four of them), to which makes Shishino basically run away, dropping his hat. Kamiya goes after him to return hat and asks him about how he deals with his beast instincts and confesses that his wolf instincts of possessiveness are taking over. Shishino thinks on it a bit and basically says that the expression of those traits will vary from individual. He met his wife (gender non specific here), before he transformed, and he doesn't feel he particularly changed his view on love. For example, even though he's a lion Beastman, he doesn't have a desire to be poly or have multiple mates and he can't comprehend those that do. He implies that whatever Kamiya is feeling could have just always been there, and that he just didn't have someone he cared about enough to feel it towards.

Kamiya and Hitomi return home, to which Hitomi realizes that Kamiya is acting a little weird. Kamiya shares what Shishino said. Hitomi gets really embarassed, realizing that Kamiya basically admitted that he loves him so much he feels all these things, and he's never loved anyone as much as him. They do the do, Kamiya is loving, but also a bit dom, and Hitomi takes the knot in. They finally do it an unrestrictive way. After Hitomi wakes up, Kamiya proposes. The end.