The first thing about any kind of abuse is to step away.
Abuse can range from emotional manipulation, to life threatening violence, and regardless of which you face, get away from the abuser.
Getting away can be as simple as opening the door and walking around for an hour. During that time, you can think more clearly and figure out how you want to handle this.
If the abuser isn't violent and isn't becoming violent, you may be able to recover the relationship. You'll need to be able to have a rational discussion with them about what's going on, how they hurt you, what may have triggered the abusive action, and how the two of you can handle similar situations in the future.
See our article on Dealing with Conflict for more.
If the abuser is not willing to discuss what happened, or your safety or sanity is in question, then you should not remain in your position.
The abuser may have some hold over you. Maybe they would have custody of a child, maybe they know sensitive information about you, or hold financial power over you.
You may need to wait a few days for an opportunity to escape with whatever or whoever they use to keep control. Regardless, once you do, you will need somewhere to go.
A quick internet search will show shelters in your area. Regional versions of this article may well have some contacts for such locations too.
These are places set up to look after and help people in exactly your situation. Even if you don't stay there, give them a call.
In most developed nations, the police will have some kind of resources and training to help victims of abuse escape their abuser. Even if you have a criminal history, even if you have legal concerns, call them. You may be an illegal immigrant, wanted for a crime, have a dark history, it doesn't matter, call the police because they will want to know about the abuser. The abuser is the problem here.
In some situations, the authorities will not assist. Often men will struggle to be taken seriously for example. In these circumstances, seek out some of the few men's shelters, you can even call a shelter in another location (another state or nation) and they may know of some ways to overcome your current problems.
Today, you're in a position where you need help. Tomorrow, you may be able to help others. Take action to protect yourself, and don't be afraid to reach out for assistance. That's what being a part of a society is all about.