Anyone who has been cheated on has likely wished harm to their philandering partner. Now, recent research shows perhaps you don’t have to do anything more than sit back and wait. Apparently, the act of cheating increases the risk for major cardiovascular events, namely heart attack, in men. 
The Risky Side of Infidelity
We’ve all seen the joke about the older man dying in the arms of his much younger lover play out in movies and on TV. Turns out, there’s some truth to it.
While research has shown that a stable, long-term, sexual relationship is associated with better overall health and longevity, “sudden coital death” has been reported in men having extramarital affairs. Of these deaths, one-third are due to coronary artery disease.
In fact, one study found that men who had sex with an extramarital partner had a greater risk for an adverse health event, independent of a high frequency of sexual activity.
Researchers hypothesized several reasons for this:
- Younger extramarital partner;
- Sex frequently occurring after excessive drinking and/or eating;
- Rise in blood pressure and/or heart rate due to excitement of the situation; and/or
- Feelings of guilt and regret, inducing psychological distress.
Regardless of the reason, they concluded, “Infidelity retains the ability to predict a higher cardiovascular risk.”
The Evolution of Infidelity
From an evolutionary standpoint, monogamy is not advantageous to the male species. Historically, the need to sire as many offspring as possible often necessitated multiple female partners.
As times changed, research found that monogamy became more beneficial to men and women alike from both a security and resources vantage point. As a result, monogamy began to take on ethical implications as well. Violating the sanctity of a marriage or a serious relationship is now stigmatized in most cultures, and unfaithfulness is seen as a violation of cultural norms.
As you can imagine, studying infidelity can be tricky. Unfaithfulness rates vary, and researchers hypothesize that they are likely higher than reported.
One report indicates that 30 percent to 50 percent of married men had extramarital sex at some point in their lives, while another report clocks in 15 percent to 25 percent of men. 
Additionally, in any given year, it is estimated that 1.5 percent to 4 percent of husbands stray. Yet, others studies put the numbers much higher, with 11 percent of American men cheating in the past year.
When it comes to social norms, researchers found the following:
- People with no religious affiliation report infidelity more frequently.
- People who attend church regularly are less likely to stray.
- Couples who do not share similar religious views are more likely to cheat.
- There is no correlation between race or ethnicity and infidelity.
- Men living in an urban setting are more likely to stray than men in a rural one.
What was particularly interesting was the conflicting data when it came to length of the relationship and likelihood of infidelity. According to one study, the longer the relationship (more than 10 years), the more likely a man was to cheat.
Other research found that the longer the relationship, the less likely for infidelity to be a factor. However, this same study did find that once the marriage hits its 18th year, at this point, the likelihood of cheating begins to increase.
As far as the type of man that cheats, researchers found a few commonalities.    He tended to have the following qualities:
- High testis volume
- High sex drive
- Higher levels of testosterone
- Higher sexual confidence
- Lower levels of guilt or discomfort with masturbation
- Fewer incidences of premature ejaculation and severe erectile dysfunction
Why People Stray
Of course, one of the big questions with infidelity is “why?” For that, researchers found several answers:
- Boredom in the marriage
- Dissatisfaction in marital sex
- Partner with sexual limitations (often due to health reasons)
- Dissatisfaction in marital intimacy
- Lower level of commitment to the marriage
- Conflicts within the marriage
Of course, there are other studies that found that “happiness in relationship is not a predictor of infidelity among men.”
Similarly, children seemed to draw conflicting points of view. On one hand, children indicated stability and acted as a deterrent against cheating, while other studies show that children cause a decrease in sexual satisfaction within a marriage, thereby increasing the likelihood of an affair.
One area that did appear to be fairly consistent was the idea of stress. Whether it was stress in the marriage, stress related to children, or workplace stress, tension and anxiety can push a man toward infidelity. And cheating may quite literally break his heart.
 Fisher AD et al. Sexual and cardiovascular correlates of male unfaithfulness. J Sex Med. 2012 Apr 17. Doi:10.1111/j.1743-6109.2012.02722.x. [Epub ahead of print.]
 Persson G. Five-year mortality in a 70-year-old urban population in relation to psychiatric diagnosis, personality, sexuality and early parental death. Acta Psychiatr Scand. 1981;64:244–53.
 Stein RA. Cardiovascular response to sexual activity. Am J Cardiol. 2000;86:37F–9F.
 Fisher AD et al. Stable extramarital affairs are breaking the heart. Int J Androl. 2011;35:11–7.
 Kinsey AC et al. Sexual behaviour in the human male.Philadelphia,PA: W.B. Saunders; 1948:282.
 Wiederman MW. Extramarital sex: Prevalence and correlates in a national survey. J Sex Res. 1997;34:167–74.
 Wiederman MW.
 Johnson AM et al. Sexual behaviour in Britain: Part- nerships, practices, and HIV risk behaviours. Lancet. 2001;358:1835–42.
 Allen ES et al. Intrapersonal, interpersonal, and contextual factors in engaging in and responding to extramarital involvement. Clin Psychol Sci Pract. 2005;12:101–30.
 Allen ES.
 Forste R and Tanfer K. Sexual exclusivity among dating, cohabiting and married women. J Marriage Fam. 1996;58:33–47.
 Kinsey AC.
 Fisher AD et al. Psychobiological correlates of extramarital affairs and differences between stable and occasional infidelity among men with sexual dysfunctions. J Sex Med. 2009;6:866–75.
 Mark KP et al. Infidelity in heterosexual couples: Demographic, interpersonal, and personality- related predictors of extradyadic sex. Arch Sex Behav. 2011;40:971–82.
 Fisher AD.
 Treas J and Giesen D. Sexual infidelity among married and cohabiting Americans. J Marriage Fam. 2000;62:48–60.
 Van Anders SM et al. Multiple partners are associated with higher testosterone in North American men and women. Horm Behav. 2007;51:454–9.
 Bandini E et al. Hysterical traits are not from the uterus but from the testis: A study in men with sexual dysfunction. J Sex Med. 2009;6:2321–31.
 Mark KP.
 Belsky J. Children and marriage. In: Fincham FD,BradburyTN, eds. The psychology of marriage.New York:Guilford Press; 1990:172–200.
 Gottman JM and Notarius CI. Decade review: Observing marital interaction. J Marriage Fam. 2000;62:927–47.