The novel translation is a little further ahead....
His thought process was that he would “protect” her by marrying kaya. Because then he would have a good reason to since they were “family”. I kind of knew that was what he was thinking and that’s why he wasn’t opposing the marriage. However he never realized that she would also be married off. Also, he knows what the family is like, did he honestly think he was going to be able to protect her? If anything they’ll probably just accuse her of seducing him and then try to kick her out or something. The dad is the worst tho. Even if it wasn’t a child from the person you loved, it’s still your flesh and blood. Did he honestly feel nothing? As far as I know, he hasn’t repented at all by the end of volume 1 of the novel.
Oh damn he really is dumb
If I were to share my opinions about the bitch's fiancé guy, he honestly kind of annoys me (not on the same level as her fams but you get what I mean) He's kind, but a coward and a pushover, although he didn't do anything wrong, it's kind of a slap in the face to say that he's the only one who can protect her (mc), when he literally did nothing when he knew that he was gonna marry that bitch and mc was gonna be married to someone who is rumored to be cold and cruel, although that has been disproven, HE doesn't know that, for all he could know, she might've still been abused... Long story short, he could've fought it through and tried to atleast try to save the mc.