We're not doing this... PLEASE don't let the MC end up with his kids...

From what I found, Seolrang is obsessed with the idea of marriage because for her is the only way they can become family. Like leon mane=family, boss=not family, how can boss become family if he isn't part of the leon mane tribe? Marriage.
And Yutia reveres him like a god, so she sees Seolrang beneath his greatness or smth.
And above everything else, he thinks of them as his children.

YOU'RE SMART, and now that I reread the chapter you're exactly right. Poor girl she doesn't understand