Me and my wife had the same problem about 3 years ago, and i know what a pain this problem can be, other the posting sleeping pills through the letter box for the dog there is'ant a lot you can do, you can keep and log of them. but the police can do very little. still wealth giving them a call. and making her know that there is a problem
i really hope you get a good ending to this.
and don't let it get between you both, its better to get some earplugs then that.
good luck