In general it is problematic to import a bourgeois individualist or isolated _nuclear_* family frame onto the early humans that probably wasn't there. There were not nuclear family units, so there isn't such a thing as a male abandoning his nuclear family unit and thereby its being less likely to survive. These are true communes , with all women in a generation being mothers and all men in a generation being uncles, mother's brothers being more the males who parent the children , etc. Plus there are not "monogamous" sexual units. There are larger kinggroup nuturing going on, not individualized , nuclear family nurturing. It took a whole village to raise a child, and the whole village was raising each child.
Of course, sociobio family theory should be criticized, but not by using its nuclear family model and finding an "imminent contradiction" in the sociobio family model. Rather it can be seen that the above sketched social structure would not support the evolutionary logic derived out of a nuclear family model of primary human cultures; the original family units in place at the time ( million years ago)when it is assumed the "evolutionary" changes took place were not nuclear families, but communal families.
With the origin of the human species, social structure , kinship becomes the main basis for human biological evolutionary adaptation._The individual's chances of passing on genes are maximally improved by participating in the kinship rules , which organize both production and reproduction , by being a member of human society, not by developing the best Robinson Crusoe ,individualist strategy._
Apes don't have kinship and kingroups. A human kin group is qualitatively different than an ape group. It organizes living society on the basis of the descent from common dead ancestors. Female-male sexual relations are organized according to kingroup traditions, "taboos" and liberties. But monogamy and exclusive sexual partners is not one of the old time taboos. That starts with the origin of "the" family, private property and the state. ( See book of that title). At the origin of socalled civilizatoin, ruling men want to know who their children are so as to pass on private property to them (!) so they institute monogamy for (against) women. This is 12,000 years ago, long _after_ human evolutionary development is settled and in an "equilibrium" in Eldrige and Gould's sense. At the point at which monogamy enters, there is no "evolution of the physcial psyche" going on, hasn't been for millenia. Humans had long ago totally differentiated themselves from apes. They were physically as we are today.
* "Nuclear family" term and concept was invented by anthropologist G.P. Murdoch of Yale. He set up the big Human Relations files or some such. Straight up "atomistic" conception , obviously, derived from the model of the "nucleus of the atom". The " nuclear " family is Robinson Crusoe-individualism expanded to the family. It is an expanded "Robinsonade" , as that concept is criticized by Marx ,et al.