Look at the marriage stats. Fewer women in all groups are getting married. Many educated women will only have one income in their lifetime. They’d better put away all the money they can if they expect to retire.
For women with a college degree, illegitimacy is less than 10%. For women who don’t finish high school, it is around 70-80% illegitimate. Even if they are living with the boyfriend at the time of birth, the majority are broken up within five years. Contrast this to two thirds of first marriages lasting a life-time.
The lack of marriage in the lower class, with the lack of economics of scale of both adults living together for decades, adds to the poverty. And the poverty is exacerbated when he divides his limited resources between multiple children / women.