It's defo this one :) https://www.mangago.me/read-manga/muhyeok_x_naui/
omg its alright lol! i lowkey jst want to re-read it but if you want more details abt it, i’ll just say it here!
- the main character didn’t really like the male lead at first because he seemed like a playboy and fcks around a lot
- the main character is a virgin
- there was a time where the main character was insecure about their appearance because when the male lead introduced him to his friends, his friends told him that the main characters looks was not the male leads ideal type
- they proposed to each other
- there was a friend of the male lead that was lowkey interested in the main character
- i think one of them smokes (?)

basically what i remember from this manhwa is that the mc is living in an apartment building and a neighbor thought that he was making all the nasty noises but it just so happens that the ml is having s*x next door (im not sure if they are next door neighbors)
the male lead is a hairstylist / tattoo artist (?), bisexual, has a lot of experience in relationships and in bed, hot, black haired dude
while the main character is an office worker (idk what kind), skinny, has a blondish-brownish hair
i do remember knowing that they both have cats
(i hope im saying all the right things lmao)