Are there any attested breakup letters, notes, or similar in classical Latin? A great number of relationships must have started and ended in classical antiquity, but I don't recall seeing any passages with the message "I'm breaking up with you". I would prefer something written, a letter perhaps, but attestations in plays or other oral forms are a good second choice. I don't really know whether such notes exist, but there must be some breakup announcements out there.
As duly noted in an answer, relationships are different in different cultures. Therefore this question is not strictly restricted to dating — although that would be preferred — but engaged and married couples are also possible. The key thing is the more or less unilateral ending of a romantic relationship.
This question was inspired by this SMBC comic, not by real life events.