What is known of Ms. Barch's ex comes mostly from her, and we can assume her perception of him is somewhat… tainted.

Apparently, they married young and stayed married for about twenty years, living mostly off her salary (she was probably a teacher at that time as well). Then, one day, he just up and left, leaving no note or explanation. Their divorce was made official five years prior to Daria's senior year at Lawndale, an event which Ms. Barch remembers as "D-Day".

He was a Broncos fan.

It can be assumed that even though Ms. Barch's bitterness is a little extreme, he must have been quite the jerk to have inspired such feelings in her.