Keep all contacts - let him leave messages and do not answer so you will have his voicemails.
You can file harassment charges against him. You do not qualify for a restraining order without a real threat (usually as demonstrated by past actions) of physical harm.
Is the MSA for the unborn baby or another child? While a protective order is not available at this time a temporary restraining order may be an option. While this is not as strong as the protective order it gives you more options.
You are not elgible for a Protective Order but my be able to obtain a Restraining Order. These are two different things. The application for Restraining Order would be filed in a civil district court as an entierly different case than your divorce. You would have to hire an attorney to pursue this. There is not a form you can fill out and turn in.
You can't ask for a protective order because you don't meet the test at this point. In order to apply for a protective order, there must have been an actual assault of family violence against the person and there must be a foreseeable threat of violence in the future. Having said that, you can request for a temporary restraining order based on the harassment.