Yur refernce, straight form Wikipedia, cites "Steven M. Platek and Todd K. Shackelford (Eds.), Female Infidelity and Paternal Uncertainty: Evolutionary Perspectives on Male Anti-Cuckoldry Tactics. Cambridge University Press: New York, 2006." However they are the only source to reference "parental effort". Yet, "males who are unwittingly investing parental effort in offspring that are not genetically their own." by it very natures is that of a cuckold, unless you believe in immaculate conception. Consider the wife & child leaving the relationship, and the husband no longer exercising "parental effort", still he remains a cuckold.
