why has the nuclear family suffered a meltdown?

They were reaching their half-life

Are you talking about John and Patty Nuclear, and their three kids?

I hope they're alright.

Progressive liberalism.

Narcissism. The idea of self sacrifice for the greater good of your family is becoming foreign

men and women are sleeping around to serve their desires, those babies made by this process if not murdered through abortion are born into selfish unstable situations to woman who are not ready to be mothers...and fathers whose only impact they made in the woman's life is a dent in the pillow

Americanism

When functioning properly, a family unit is the smallest form of a sovereign state. Its sovereignty has to undermined if government wishes to exert more control over individuals. But, on a spiritual level, the destruction of the family as God's design for man is of satanic origins. Satan hates humans and wants to see them destroyed.

People have other things to do than have babies and raise cows. Women have jobs and a life. Men have jobs and a life. So they have maybe one or two children.
Before women washed clothes on a wash board and hung them out while pregnant. Now they have washers and dryers and dish washers and jobs.

The other thing is that the gods punish mortals who harm the beasts of the shadows

Because so many have removed GOD and LOVE from their lives!
Atheists and fake god believers canNot feel anymore then LUSTs for only their own wants!

Feminism... Because birth control is widely available and most women are having only one or two children, women now prefer to depend on the welfare-state, live in poverty and be single parents, rather than obeying a provider/husband and having six or eight kids.

Don't misunderstand me though, I think human population control is a very good thing for the Earth and all its inhabitants.