I'm a bit worried about going into to many details, but there's a couple and infrequently (once a year maybe?) a simple argument will become much more and one party will say the other is abusing them/driving them to self harm (by not agreeing with them) and then will go on to physically hurt themselves or smash up their own stuff.
The other party doesn't believe they are being abused as it's never them/their stuff being damaged, but this feels like an attempt to control to me?