If he persists in contacting you after you have told him the contact is unwelcome, and it is causing you emotional distress, it is probably sufficient for a criminal charge for harassment or stalking. If you don't want to file a criminal charge, you can still apply for a protective order. If he continues to contact you in violation of the order he can be charged with that.
Contact your local prosecutor's office or domestic violence advocacy office and they can give you more information about how to proceed.