Help! We have already sent out our save the date cards and they were written out to the exact people we intent to invite to the wedding. A co-worker who has made it well known in the office that he and his wife are separated (have been now for about 2 years and live in separate homes but still have, uh, visits to put it politely) said he received the save the date card and called his to-be-ex and told her about it and is having her come with him to our wedding. My fiancée and I budgeted according to our guest list and we are only allowing a +1 for guests with spouses or engaged. What would the etiquette be in this case since he clearly didn't understand that seeing only his name on the save the date means that only he is invited?
Thanks!