Should I continue to call the cops every time my neighbors argue?

On a daily/nightly basis my uptairs neighbors fight. These arguments last around an hour or more. I don’t get too upset when it’s during the day, but when it occurs at 2:00 am like it did yesterday, I get very angry. One time I actually sat there and listened to the entire argument just so I could understand what two people could possibly argue so much about. It was shocking. The husband comes home drunk and for no reason starts to pick fights with his disabled wife. He calls her “retarded” and “good for nothing”. She’ll try to say something and he’ll immediately cut her off by telling her to “Shut the hell up right now. You don’t matter.” It makes me sick. I believe it’s gotten violent. I think I have heard her saying “Stop it! You’re hurting me!” Just the other night she was so upset she actually made herself sick. She was vomiting for quite awhile. The whole time he kept talking down to her and disrespecting her.

Besides the fact that my s/o and I have gotten almost no sleep since these people moved in, now it’s upsetting us because the guy is verbally and possibly physically abusive to his wife. I called the cops last night around 2am when they started arguing again but they never did show up. In fact, I watched a sheriff pull into our parking lot and pull out quickly. He never came back. And sure enough, first thing this morning the neighbors were at it again.

What should we do? Keep calling the cops each and every time? Write a letter to the landlord about the noise problem? Isn’t it the cops obligation to respond to domestic disputes? I’m so frustrated with this. I’m going on very few hours of sleep and I’m pregnant. Please help before I go insane!