Dear Miss
If he is an Ethiopian, resides here in Ethiopia He will probably knew what to do. Don't worry much. Just in case if you two guys are abroad for some reason, you need to contact nearest Ethiopian Embassy for further information. In fact, you have to have a proof of Single status and may be your marriage certificate of the traditional ceremony from Zimbabwe (like certificate from church and related proof). Hope my comment helps you. Have a pleasant wedding Miss.
your Ethiopian brother from another mother.