We need a term for our lovers’ exes

There are plenty of words for extended family members…sister-in-law, stepmother, stepbrother, and so forth. But when you’re referring to the ex of your current spouse or lover, there isn’t really a term to use except, for example, “my boyfriend’s ex,” or “my wife’s ex-husband.” We similarly lack a term that works for both parties, like “stepbrothers,” to describe, say, the relationship between Ashton Kutcher and Bruce Willis, or Angie and Jen.

I suggest we come up with one sooner rather than later. The only thing I’ve been able to come up with so far is a one-way term for casual references to a current lover’s ex. The term I propose is “predesexor” or “predesexxor” (depending on your spelling preference). As in, “I was at the bar last night, and I totally ran into my predesexor! She asked how Matt was doing and I wanted to kick her ass.”

But as for a two-way term that either party could use, I’m stumped. Besides the gender-specific “Sister Wives” from polygamous groups (and “Big Love”), which really only applies to current relationships, I can’t really think of any term that’s descriptive and universal enough. Any ideas?