Cuckoldry is rare

https://www.nytimes.com/2016/04/12/science/extra-marital-paternity-less-common-than-assumed-scientists-find.html

http://www.cell.com/pb-assets/journals/trends/ecology-evolution/tree2086.pdf
http://rspb.royalsocietypublishing.org/content/280/1772/20132400
https://phys.org/news/2016-04-cuckolded-fathers-rare-human-populations.html
http://www.pnas.org/content/109/25/9781.full

https://heartiste.wordpress.com/2016/04/07/cuckoldry-culture/