Beth61 a sad dilemna..but if his behaviour was bad enough to warrant disclosure under Claire's Law, it might be worth as others have said, telling the support officer. You never know the woman might have a child or children, as well as for her own safety.
If he assualted your DGS, it would be a worthwhile thing to do, to let the police know so the woman has at least a chance to protect any children connected to her, and herself.
Kate Garroway-Care at home costs
Things you find stressful that other people don't notice.