I hate it but I get what you mean. This was unfortunately a necessary to happen not only to show how broken their relationship is but to make seme’s real self if that make sense. It’s heart breaking but I hope in s2 it would be better.
Now that i read the translation I can see that S2 will bring on that rival from the north. He looks like an alpha character that will most likely have a huge role in Yeonjo's salvation at some point. He's described & represented as a powerful man. He may further separate them before contributing to bringing them together for good. Exciting!
Sweet delicious angst! Season 2 can’t come quick enough! And yes, I do think this rape scene was absolutely necessary to tell the story the author is wanting to tell. Their relationship is totally damaged, which is why it will be interesting to see how they reconcile.