When monogamy is permanent and divorce unavailable, males face a straightforward calculation: invest in one female to secure her paternity confidence and reproductive capacity. The female's best strategy is to secure investment from a high-quality male willing to commit exclusively. The system produces relative stability in mate choice.1
Yet when divorce becomes possible—when pair-bonds are terminable—the entire strategic landscape shifts. Males now face mate competition not just at initial pair formation but continuously throughout the relationship. A female can always leave for a higher-quality male if one appears. A male cannot assume the female's future reproductive capacity is secured.2
Serial monogamy creates several predictable effects on male psychology:
Increased Mate-Guarding: Males become more concerned with monitoring female fidelity and restricting female autonomy, because the consequence of female defection is not just loss of current offspring but loss of future reproductive capacity. The female can leave with the children or refuse future reproduction.3
Status Insecurity: Males become more sensitive to status competition with rivals because status directly affects mating competition. A male who loses status in a serial monogamy system risks losing his current partner to a higher-status rival. This creates chronic status anxiety that wouldn't exist in a stable pair-bonding system.4
Risk-Taking: Males in serial monogamy systems show increased willingness to take risks (financial, physical, reputational) to improve or maintain status. Status loss is catastrophic because it threatens mating access. This produces higher risk mortality in divorced populations.5
Parental Investment Conflicts: Males in serial monogamy show greater ambivalence about investing in stepchildren, since investment in a partner's children from a previous relationship produces no genetic payoff if the current relationship terminates.6