I have had to deal with this situation with my sister when she was young. I never fully understood why it happens but it seems like an weird devil you know versus devil you don't kinda thing. My parents split when I was very young so kinda became the defacto man of the house when I was really young and would alway make sure sister was safe. I always looked after after my sister and tried to guide her but also let her live her own life and only got involved when she asked for help. I knew something wasn't right when she started dating this gangster wannabe kinda guy and she phoned me one night and explained the whole situation. Very long story short he wouldn't let her leave and was holding all her stuff hostage so I gave him a call while she was at my Mom's. Told him I would be out front of his house in half an hour and he threatened to shoot me (my sister warned me he had an unregistered gun) regardless I told him we can talk when I get there. All her stuff was outside and he was nowhere to be seen and anytime I ran into him after he would never make eye contact. Seems like a weird dominance thing until someone confronts them. She was also a server back then and used to get harrased by many regulars who would be very pushy for her number so she would give them my number. If a male phoned me and asked for her I would know what's up and tell them why she gave her my number and tell them never to talk to her again and they never showed up at her restaurant. I would have to do this at least once a month. It's insane the amount of harrasement women have to deal with.