I'd be working with the social worker at getting some sort of restraining order against the bloke.
I'd also be looking at sole custody of your son due to child protection issues, a judge would have no issues with that. I'd also look into it then speak to the mum and tell her what you are going to do if she gets back with him.
Local papers with his name and what he's done, with a photo maybe, shame him into leaving the area.
And while violence has been mentioned in this thread, resorting to that will destroy any case you may have for custody. You just have to suck it up and not react to it if you want to do what's best for your son.
I'd also be looking at sole custody of your son due to child protection issues, a judge would have no issues with that. I'd also look into it then speak to the mum and tell her what you are going to do if she gets back with him.
Local papers with his name and what he's done, with a photo maybe, shame him into leaving the area.
And while violence has been mentioned in this thread, resorting to that will destroy any case you may have for custody. You just have to suck it up and not react to it if you want to do what's best for your son.