The writer is freaking annoying. Wtf? They literally build up the entire backstory of the characters by talking how they BEAT OTHER PEOPLE UP ALL THE TIME
Then for some reason he's giving this new girl plot armor? If it was actually keeping in touch with how the characters are, the FL would have beat her up so hard already for literally bullying her boyfriend. Either she doesn't actually care about him that much, or, what's 100% more likely, the author sucks at writing.