Honestly, the three MLs were more like extras; it's the past story that's the gold. The real story was about the two sisters who share a deep bond.
I enjoyed how trauma was conveyed realistically. Both sisters suffered so much and are healing from their trauma. The protagonist hates all three MLs and initially you'd think it's the "I hate them but I actually enjoy the attention" trope that 90% of stories share, but then it's clear that she actually hates them and is afraid of them because of her trauma.
The end was sweet, almost too sweet and rushed compared to everything they went though, but I'm willing to brush it off.
By the description blurb, I thought I wouldn't like this one. Yet it zigs a few times against the normal paths these stories tend to take, it treats the trauma element seriously, and doesn't refuse to write an ending. It focuses on the psychological ramifications rather than sensationalized physical ones. It shows the different ways to react to situations without harsh value judgments. It won't be everyone's cup of tea. Large swaths of it are depressing. Not every character is likable. Occasionally events/dialogue lines are muddy (and that doesn't seem to be translation errors).