Skip to main content

Verified by Psychology Today


Why Women Have Affairs

Reasons for female infidelity

Dari Ya/Shutterstock
Source: Dari Ya/Shutterstock

Dating sites such as,, and to name just a few allow people the opportunity to connect with others for the purpose of having an affair. While this article does not discuss the rights and wrongs of infidelity, research nevertheless seems to suggest that it is fairly commonplace. For example, back in 2004 David Schmitt’s world-wide study involving several cultures found that 60 percent of men and 40 percent of women had made an attempt to steal another person’s partner. The findings of this study also revealed that 60 percent of men and 50 percent of women have succumbed to the advances of a pursuer at some point in their lives (Schmitt and the International Sexuality Description Project, 2004).

The Risk of Being Unfaithful

The risks of an affair can involve a loss of reputation socially, rejection by a partner or even physical revenge by a partner/ex-partner, however females compared to males face the additional possibility of pregnancy and a period of time invested in rearing a child. Given this extra risk the question arises as to why females risk being unfaithful and what possible benefits they might gain from this? David Buss’s paper on desires in human mating offers several possibilities as to why females might risk infidelity and the possible benefits of this (Buss, 2000).

Reasons for Infidelity

In his paper, Buss cites numerous reasons from a variety of sources as to why females might engage in infidelity. Generally the benefits of infidelity for females may be grouped under two categories which are to ensure reproductive success and secondly to receive some form of external advantage. More broadly, females might engage in infidelity to increase their likelihood of having children or to produce stronger children, or they may do this as a means of securing some form of external benefit or to elevate their status in some way.

1. Ensuring Reproductive Success

The better genes hypothesis suggests that having sex with a man possessing better genes than a female’s regular partner (e.g. genes for higher intelligence or genes for greater athleticism) would be advantageous because this will mean that any offspring resulting from this encounter will also possess these genes, thereby giving them advantages in life, such as a better job earning more money or with greater status. Furthermore, a female may be motivated to be unfaithful with a male who is attractive, because this will increase the chances that any sons will themselves be attractive, thus increasing the probability that a female will have grandchildren (referred to as the sexy son hypothesis). Female infidelity may also be driven by the strategy of genetic diversity. A female who has children with several males will produce genetically different offspring, giving each a chance of success in different or changing environments. For example, one child might inherit intelligence, whereas another might inherit physical strength, with the possibility of each characteristic being advantageous depending on the environment they inhabit. Finally in terms of producing offspring, the fertility backup hypothesis suggests that a female whose partner might have reduced fertility may benefit from a sexual affair, in order to make it more likely she has children.

2. Acquisition of External Benefit and Elevation of Status

In terms of receiving some form of external benefit, the resource accrual hypothesis suggests that females may be able to exchange sex for resources, such as money or gifts, although in our evolutionary past this may have been food or shelter. Furthermore females may also exchange sex for protection, possibly for their children and other family members. Previously this would have meant protection against harm from wild animals, or perhaps even protection from exploitation by other humans. If a regular partner were unable to provide such protection due to being absent, then a female may have been able to obtain resources or protection by offering sex to another male.

The enhancement hypothesis suggests that a female might elevate her status among her peers or possibly gain access to higher social strata, by engaging in a sexual affair with a man of higher status. It is also possible that by engaging in infidelity, females may be able to improve and enhance their attraction and seduction skills, referred to as the honing mating skills hypothesis. Enhancement and honing skills serve to increase a female’s judgements of her desirability to other men, resulting in an elevation in self-esteem. The consequence of this might be an improved ability to make mate choices ultimately leading to mate switching, meaning that a female may have an affair in order to expel her present partner, and in the process acquire one who is superior.

The Evidence

In addition to the above reasons, it is likely that a female would find desirable a different partner who is more interested and committed to her, and is more attractive and compatible than her current partner. Therefore, Buss notes that in several studies receiving sexual gratification is also a reason commonly cited for infidelity. If sexual relations with a regular partner are unsatisfying then an affair with another male may be a positive move.

Overall however it seems that the mate switching hypothesis and the resource accrual hypothesis are those which have received greatest support from the evidence. The possibility of having a superior partner in addition to receiving money, gifts or career progression from engaging in infidelity may be advantageous, especially at a time when a female’s present partner may have poor prospects in comparison to an alternative.

Visit my website

Follow me on Twitter @martingraff007

and YouTube


Buss, D. M. (2000) ‘Desires in Human Mating’ Annals of the New York Academy of Sciences 907 (1), 39–49.

Schmitt, D. P., International Sexuality Description Project (2004) ‘Patterns and Universals of Mate Poaching Across 53 Nations: The Effects of Sex, Culture, and Personality on Romantically Attracting Another Person's Partner.’ Journal of Personality and Social Psychology, 86(4), 560-584.