Late 80's Absent fathers

When I was young, I lived in America in the mid to late 80s, and almost every everyone I knew was being raised by a single mother after the father ran out on the family. It seems like most men that were born between 1945 to 1965 were just hopping around creating new families and then leaving them. WHY? several of the kids I was friends with weren't from the first family the men did this to. I've always wondered this.