A new international study has found fathers who invest time and money in their children are likely to be more jealous when their partner cheats on them compared with dads who are less involved.
Dr Geoff Kushnick, an anthropologist at The Australian National University (ANU), was part of the research team. He says while previous studies had focused on differences between the sexes, this study investigated cultural differences including fathers' involvement in their children's upbringing.
"The critical finding from across the various populations we surveyed was that the more fathers invested in their kids, the more jealous they would feel if their wives or partners had sex with someone outside of the relationship," said Dr Kushnick.
"Whether a person lives in a small village in Indonesia or in a bustling Los Angeles neighbourhood, norms regarding sexuality and fatherhood can have a big influence on the jealousy someone feels when they are betrayed by their life partner."
The team, led by the University of California, surveyed 1,048 men and women from 11 populations around the world, including urban areas in the US, India and Japan.
"We presented each respondent with a number of scenarios where they experience infidelity, such as their partner having sex with someone else. Then we asked them to report their feelings of jealousy on a five-point scale," Dr Kushnick said.
"Cross-cultural research of this sort allows us to better understand how human behaviour is shaped by the social context, and to get past generalisations about how males behave or how females behave."
Dr Kushnick said men tended to have less involvement in their children's lives in female-dominated societies, such as matrilineal systems, where fathers were not expected to provide ongoing support.
"Fathers in these societies have a less severe jealous response to extramarital sex than those in other societies where they player a bigger role in family life," Dr Kushnick said.
The study is published in Nature Human Behaviour.