I'd do both. In my experience the police are most definitely willing to keep an eye on things if there's a domestic dispute likely to happen. On the other hand, if that's "his" house, I suppose he's allowed to destroy it if he wants to.
But, really, what can it hurt to ask?
The chances are probably good that he's not gonna do anything this weekend except sit on the couch and get drunk, dontcha think? He's most likely just quacking when he talks about having a big party. Whoop deee dooo.