Well, let me tell you a couple of stories.
My ex would wake me up in the middle of the night, screaming and yelling about imagined slights. He'd leave for work in the morning and then double back and watch the house from down the road, just to "make sure" I wasn't "doing anything wrong". If I was going out of town to visit my parents, he'd show up out there in the middle of the night (it's a 2.5 hour drive), just to make sure I was there. He'd have the phone shut off, have the internet shut off, siphon the gas out of my car so I couldn't leave the house without him. He'd have me removed from bank accounts, report my credit cards stolen, etc.
The last 5 years of our marriage, I never knew from one day to the next if I'd be able to buy groceries, or even drive to the grocery store. There were plenty of days where I couldn't have driven the kids to the ER OR called 911 because there was no gas in my car and no functioning phone in the house. (and we live 25 miles from the city)
But he never laid a hand on me. Sometimes, I wished he WOULD hit me. So I'd have something concrete to base my fears on. I would have felt less crazy.