Hi Strube,
If you can try to keep your cool and don’t lower yourself to his pathetic level, your kids will see him as just that in comparison- pathetic.
These men don’t care what damage their words do, even to their own children. In fact, they don’t even think that far- things begin and end with them.
Keep on being the loving and caring mum you are. My first counsellor told me that kids go where they feel most loved. If you are careful about their emotions, they feel loved. His horrible insults can’t seem like love for them. He’s using them as weapons and as an audience for his own frustrations.