"My ex sat outside my apartment in her car for periods of time to stop women from entering and questioning them, telling them not to talk to me because I was a psycho. She did the mistake of pulling my sisters hair, she competes in kickboxing."
WhySoSeverusSnape
That is something I will never understand.
There is this thing called infatuation - it is like a drug that makes people almost unable to find minor faults with each other until it is over, it can last for between 1 and 3 years. All the redflags are obvious in hindsight or from neutral observers perspective, also if someone was burned previously they will learn to spot the early signs out of necessity.