Hiding in the truck

Our children have started to witness  domestic violence in their dad's home, between their dad and his current wife. One evening a few months ago, KR and his wife GR got into each other's faces and started to tell F*** you at each other. ( The arguement revolved around GR saying she didn't want our boys at her house anymore) Then KR raised his fists and put them in front of GR's face. The boys were afraid that the fight was going to get physical,  and because the fight was about them, that it may turn physical against them, so they ran outside and hide in one of the trucks. They could still hear the arguing,  and see KR threaten GR with his fists. The boys said they fought for along time and they stayed out in the truck until it got dark, and then went inside because they were cold.  Our daughter was still inside. She heard KR tell GR that he was going to divorce her. It upset our daughter. Later that night, she asked KR if he was really going to divorce GR,  he told her no, he was just teaching her a lesson.  It saddens me that our children are exposed to toxic relationships, are are told they are not wanted.