@Eis
It's based on Asian values, if anything. If parents give children an education fit for them and give them a life of financial stability, that's the best thing they can do. And the original ex-bf was unreliable—he wasn't willing to fight for anything. If push comes to shove, would he protect Su Yan? With that mentality, they handed her off. In their eyes, ML was the best and they chose the best for their daughter. In their eyes, they truly thought they were doing something good for their daughter. By doing this good, they also benefitted all the family, killing two birds with one stone, essentially.
Not that I'm excusing what they did but I think this fits better with eastern values.
I think the original Su Yan was very pitiful. Until her death, this is what she suffered. No one listened. I guess this is why I'm not too big on transmigration stories.