When does emotional abuse via email become illegal? I'm constantnly being threatened by my ex with fraudulent allegations

Is there any reason (such as a common child) that requires the two of you to remain in contact? If not, you may be able to petition the court to prohibit your ex from contacting you. Even if there is a common child, the court may be able to order the ex to limit the communications to issues about the child.

While court clerks are generally prohibited from giving legal advice (including what to put on forms), someone in the courthouse usually helps the public in filling out forms relating to domestic violence. The filing fees for your petition may also be waived.

If there are threats of physical violence, that may be a criminal matter.

You should review the specific facts with your attorney to find out what legal options are available to you.