Mate Switching Hypothesis

Definition

The mate switching hypothesis proposes that some affairs function as assessment, preparation, or transition toward a new primary partner rather than only as pursuit of sexual variety or reproduction with one partner while retaining investment from another.

Current Synthesis

David Buss contrasts mate switching with the dual-mating strategy hypothesis. The latter proposes combining investment from one man with genetic benefits from another; Buss says he moved toward mate switching because many women reporting affairs also report emotional involvement or falling in love with the affair partner, while later larger ovulation studies weakened earlier cycle-shift findings.

The hypothesis is not a universal explanation for infidelity. The source reports different common motives by sex, measurement difficulty caused by concealment, and distinct sexual, emotional, and financial forms of infidelity. It therefore supports a possible pathway from relationship dissatisfaction to re-pairing, not a rule that every affair is an exit strategy.

Key Claims

• Some affairs may evaluate or establish a replacement partnership.
• Emotional involvement with an affair partner is more consistent with switching than with a genes-only account.
• Larger ovulation studies weakened some evidence previously used for the dual-mating strategy.
• Infidelity motives differ, and opportunity, variety, dissatisfaction, attachment, and relationship context may overlap.
• Sexual, emotional, and financial secrecy should not be collapsed into one behavior or motive.

Evidence

• Competing accounts: How Humans Select & Keep Romantic Partners in Short & Long Term | Dr. David Buss directly contrasts dual mating with mate switching.
• Emotional involvement: How Humans Select & Keep Romantic Partners in Short & Long Term | Dr. David Buss says many women who have affairs report love or sustained emotional involvement with one affair partner.
• Replication update: How Humans Select & Keep Romantic Partners in Short & Long Term | Dr. David Buss says later larger ovulation studies weakened or failed to replicate parts of the earlier preference-shift evidence.
• Motive heterogeneity: How Humans Select & Keep Romantic Partners in Short & Long Term | Dr. David Buss reports opportunity and variety more often among men who cheat and primary-relationship unhappiness more often among women who cheat.
• Infidelity scope: How Humans Select & Keep Romantic Partners in Short & Long Term | Dr. David Buss separates sexual, emotional, and financial infidelity.

Counterevidence & Qualifications

Affairs are concealed and difficult to measure, and self-reported motives can be incomplete or reconstructed. Emotional involvement does not prove that switching was the affair’s original function, and sex averages do not classify an individual case. The note provides no full datasets or causal tests, so both the mate-switching and dual-mating accounts remain source-scoped hypotheses rather than settled universal explanations.

What Changed

• Created the hypothesis as Buss’s evidence-responsive revision of an earlier dual-mating account.
• Added motive heterogeneity and measurement limits to prevent universalizing the model.

Related Concepts

• Evolutionary Mating Strategies - parent framework for switching, retention, and short-term mating.
• Jealousy and Mate Retention - defensive response to cues that a partner may defect or re-pair.
• Mate Value and Mutual Choice - comparative evaluation that may affect perceived alternatives.
• Relationship Optionality - broader frame for alternatives, commitment, and exit.
• Shared Relationship Narrative - emotional and narrative bond that may shift toward an affair partner.