According to Buss, more men than women want to have sex with multiple partners. Furthermore, women who cheat on their husbands do so when they are most likely to conceive, but have sex with their spouses when they are least likely to conceive. These findings show that evolutionary tendencies to acquire better genes through different partners still lurk beneath modern sexual behavior. To counteract these desires to stray -- and to strengthen the bonds between partners -- jealousy evolved as an early detection system of infidelity in the ancient and mysterious ritual of mating.

Buss takes us on a fascinating journey through many cultures, from pre-historic to the present, to show the profound evolutionary effect jealousy has had on all of us. Only with a healthy balance of jealousy and trust can we be certain of a mate's commitment, devotion, and true love.