Tournament species are where the top males are the only ones who breed, such as lions, mountain gorilla, peacocks, certain types of fishes where two sexes exhibit different characteristics beyond the differences in their sexual organs.
Pair-bonding species are where the mates seek each other monogamously with less competition. In the animal kingdom, pair-bonding species are usually life-long, such as penguin, swans, wolves, and certain birds.
Humans are a hybrid of the two. A different individual may fall into different places on the spectrum. Tournament women are common, so it’s unsurprising that a signifacaint amount of men have issues with trust.
Benc Tan 