Like bohemian, I also have neighbours who fight and it's the woman who is the aggressor; usually when she's had a drink. To the outside world, this couple have everything you could possibly want in life, beautiful home, lovely children etc, but the husband is beaten up on a fairly regular basis. I only became aware of it when he knocked on my door, very late one night, bleeding badly from cuts to his face and hands. She'd thrown him out, wouldn't allow him back in and he had no money to go to the Travelodge that he usually used when this happened. Apparently, he'd spent the night sleeping in his car on previous occassions too. But despite repeated occurrences, he flatly refuses to leave, or seek professional help.
Never in a million years would I have thought that this particular couple would have had this problem. It's very true that no one knows what goes on behind closed doors.