I'm not emotionally invested either (which is why I would never have camped out on the street in front of the house) other than caring about all young women's vulnerabilities. I know the outcome of Gabby's fate and who her belongings ended up with, not much there to allow me to change my mind about Brian.
Okay, you want me to turn to Gabby. Well, likewise, I don't think Gabby was emotionally mature either. Not in an arrested development way but in a non-worldly, limited life experience kind of way. I don't think her acting out in a physical way towards him was violent, I think it was her only known method of "conflict resolution" as a child might do. His comprehension of that meant she was "crazy" or "OCD". Your scenario is exactly what I envision having happened. And it doesn't change anything.