Over human evolutionary history, men faced the adaptive problem of cuckoldry, or
the unwitting investment in genetically unrelated offspring. As cuckoldry is
potentially so reproductively costly, men may have evolved anti-cuckoldry
psychological adaptations. Sexual coercion has been hypothesized as one class of
anti-cuckoldry behaviors. By sexually coercing an intimate partner, a man may
reduce the risk of cuckoldry by placing his sperm in competition with a rival male's
spenn, should his partner have been sexually unfaithful. I will present three studies
that investigate the role of female infidelity, an assessment of risk of spenn
competition and subsequent cuckoldry, in predicting male sexual coercion in the
context of an intimate relationship.