I mean they didn't got the chance to know each other and suddenly hye-sung got pregnant. Even tho it looks like they've knows eachother for so long, they know each other for only 3 or 2 years. I even have friends i've known for 8 years and sometimes we understand that we don't know eachother that much.
Yeah, I agree. Hyesung basically got forced into this situation so he probably just accepted it and got used to it. It's not like he had much choice. I feel like if maybe Dojin weren't so toxic Hyesung could develop some feelings towards him (there are scenes where I see some potential) but Dojin self-sabotages himself with his manipulative behavior.

this really frustrates me, like I get dojin feelings probably I would feel the same if it was me but he handled them and expressed them in the most toxic way, hyesung at the other side after 90 chapters still seems to have little to no feelings for dojin. He sure loves byul but about dojin idk, their relationship seems pretty plain, it’s more like hyesung just got used to live with dojin and nothing more