Notes: A very common approach to referring to a former partner (such as a former boyfriend) is to spell "EX" prior to signing BOY FRIEND instead of using the sign OLD.
I couldn't imagine someone signing "MY OLD WIFE" to mean "ex-wife." So even though you can use "OLD" to refer to a previous boy or girl-friend I recommend that you don't use "OLD" for referring to former spouses.
 When referring to a "former but no longer" lover -- of the two signs "OLD" or "EX" the safer choice would be to use "EX."  My reason for including the sign OLD in this curriculum is to help point out that it does indeed occasionally express a  meaning other than "long in age."