Tbh, I get what the author was trying to deepen the plot by introducing the grandfather which I don't mind. But the execution was just bad. Instead of gradually building up to a non-concensual breakup and letting things develop naturally, they skipped ahead and just gave us aneurysm with the break up.
And throwing rape into a manhwa that's been mostly fluffy and cute the entire time felt unnecessary. It was such a jarring tonal shift and didn't add much beyond a shock value.
They have the idea, but they don't know how to deal with it. And the thing about the grandpa, it would be better to introduce early in the story so that they didn't face the dead end. They could go with accident, or attempt kidnapping, but maybe it's too common that they decided to add rape as the reason why they separated...
I get what you mean. The grandfather suddenly became a major part of the story even though he'd barely been mentioned before, with only a few vague references here and there. And suddenly he's shoved in our faces.
The author probably wanted to make the story more interesting, like you said, by giving it more depth. But to ultimately deciding to use rape to achieve that is such a diabolical choice. ╥﹏╥



Taesung should just accept the offer to kill that coffin-dodger and put an end to it, so they can finally be together again.