Not-so-ex

When you had a thing with a guy/girl and the two of you were very close and were almost practically dating but for some reasons you never ended up putting a label on it.

-You'll never guess who I just passed, my not-so-ex!

-Omg, that guy you had a thing with but never ended up dating?
-Yeah... Him... And just to be clear, the girl over there is the one who ruined our so-called relationship...

Not-so-ex

When you and a guy/girl had a thing and were almost dating, were very close, but for some reasons you did not end up together or putting a label on it

I saw my not-so-ex today...
Henry? The guy you had a thing with but you guys never ended dating...?