This love story is also a time-travel story. Due to some kind of curse, the male protagonist had to go back in time and separate himself and his beloved, just to save his son. However, the male protagonist in the story did not know all this yet. He thought that everything was just a decision of fate that separated him from his beloved, so he warned his son to be brave when facing love and not to miss it, so the ending was not bad, not too cruel.
Purpose: Sometimes life requires courage and decisiveness