Advice, Restraining Order

I know this really isn’t the place such personal matters but I really don’t know what to do and wanted advice from a neutral party.

I have been getting threatening responses from my child’s father. He is upset about me having a new boyfriend and refusing to give him my new address. He has said he would make my life a living hell, told me that I better fear him, he would take my son from me and my boyfriend would end up dead. I’m just scared because I really don’t want my child not so have his dad in his life but also know I need to make the right decision for everyone’s safety. I don’t know why I feel lost in the matter.