Don’t let him blackmail you ? How does he know about social services? I’ve been in your situation and I was blackmailed over this by my ex , I stayed out of fear , made same mistake you did . Cut all contact and stop responding, the more you engage , the more it goes against you if it were to come out . Do not lose your children over this man , he is not worth it . If he does tell them which I doubt you can say he has been Harassing you and you were in fear and he was blackmailing you to continue contact . You unfortunately opened the door , I did same , now shut it firmly behind, before he causes any more damage . You gtta try and protect yourself and your children, he will use social services against you as a tactic to keep you in the relationship. X