Most of his arguments for the nuclear family have a basis in evolutionary psychology, and this seems to be the case for his support of the nuclear family. The nuclear family, however, appears to be a more recent construct. For most of human history, early death was common, and we had flexible familial structures as a result. Only when we had plenty of food, vaccines, and antibiotics did we really begin to see stable families form.
And even then, I have to wonder how beneficial these familial structures were for women.