What's the difference between i.e. and e.g.?
1827, originally short for ex-Catholic; ultimately from Latin ex (see ex-). Since 1929 as abbreviation for ex-wife, ex-husband, etc. Also used in some commercial senses for "from, out of."
A former wife or husband, girlfriend or boyfriend, etc: He introduced his ex rather casually, considering they were together 27 years (1929+)