Always call 911 if your life is in danger. But for any other domestic problems, DONT CALL for help. Your spouse manipulated you into takinng abuse, and you can be damn sure he/she will manipulate the police too.
Abusers have a deep need for control... and so do the police! (why else would they want that job??) so you can be sure that the police will identify with your abuser. If you call the police for help with domestic, you may be called a liar, beaten, or even arrested!
They may also enable your abuser by telling him it's okay and they understand, or worse.
My abuser would not give me my belongings, and I had to get a court order. The judge ordered that the police assist me in getting my belonging (for safety). My abuser packed a few things up and said that's all I could have. Even though I had a court order, the police agreed with him. When I went to try and get other things, the officer screamed in my face and threatened to arrest me!
I have filed a complaint with the commission, but I am confident it will get thrown out, since the police have the authority to abuse people and they certainly don't need to follow laws or court orders. I can understand though, after all, they DID take a 6 month training course!
That is only one example of how the police have wronged me since I left my abuser. There are many more incidents.
Moral of the story, DONT CALL THE POLICE.