Of course. But with physical violence, it's much easier to tell when it starts. That's why drawing a zero-tolerance line with it is possible. With emotional abuse, there is not as clear line, because it's so invisible.
Also, physical violence can kill a person instantly. There doesn't even need to be intention to kill, unlucky punch can do that. Any other form of abuse can't really end ones life so quickly. That's why I think physical violence shouldn't be tolerated at all if there is a chance to get out.
Actually research shows that violence is the last thing to come in a abusive relationship. So by the time that the partner uses violence they are all ready controlling many things
Finance - causing lack of money to leave, dependent on partner
Abuse - brainwashing , scream, threats ( like I will take the children if you leave, no one will believe you ), mocking, humiliating.
Friends and family - only allowed out with partner, cuts you off from friends and family, isolates you.
Also note that the most dangerous time for women is when they leave their partner, and afterwards. This is when a lot of the deaths takes places. Of course that is not exclusive and can happen anytime.
Note my abuse never was psychical, but a week before I left, he was going to "push" me down the stairs but my little one appeared and stopped him.. I was challenging his power.
Also it takes a women 7 times to leave a abusive partner. It is very hard and complex situation, we should never judge anyone in that situation.
They do say their is warning signs when dating someone, slightly warning signs that unless you were aware of them you would notice.