At the same time, sexual intimacy does a lot to bring two people closer, both physically and emotionally. Even the most straight-laced traditionalists will admit that intercourse can help strengthen or perfect the relationship. It functions as glue to keep together a couple while they collaborate in bringing up their offspring. Then, a good shag can contribute to maintaining the cohesion within a couple in various ways, for example by preserving the necessity of romance, by easing the natural irritation of living in close quarters with another person, or by fostering familiarity, receptiveness, and forgiveness. Thanks to sex, fondlers (who do not necessarily have to be parents) feel more connected to each other, be it through the amorous exchange of compliments during foreplay, the time spent both bodies entangled in one another or the post-coital pillow talk. Moreover, as soon as true love is involved, physical contact facilitates the expression of that love, which thereby acquires depth and intensity. Even if the sexual act does not ultimately lead to a partnership in the long term, both actors know one another better than the rest of the world ever will. These arguments may also explain why some people claim that sex is better with someone we love. In their opinion, the most gratifying sex is the product of the “kind of mind-body connection that comes from good communication, lower inhibitions, and less pressure to be perfect”.
As elucidated in other chapters, this emotional interconnectedness results from the release of hormones (specifically, oxytocin) during sex, which trigger feelings such as affection, trust, bonding desires, romantic attachment, etc. In other words, human biology rewards us for our effort to seek arousal and intimacy with a healthy dose of well-being. These brain chemicals are responsible for the good mood that people experience during and after congress. This property turns sexual activity into a superb stress reliever and a highly effective agent for falling asleep or for relaxation in general. According to one source, sex is about ten times more efficacious a tranquilliser than Valium! Although the oxytocin produced in the course of orgasm accounts for most of the anxiety-reducing and contentment-elevating effects, climaxing is not necessarily a prerequisite for these to kick in, at least not for women. That should be good news for them since reaching an orgasm through intercourse is usually much more difficult than for a man. Rather, studies show that semen itself contains a number of hormones and other compounds (e.g., testosterone, estrogen, prolactin, dopamine, norepinephrine, vasopressin, prostaglandins) that have potential mood-altering characteristics. After entering a woman’s bloodstream through the vaginal walls, these chemicals can then unfold their curing functions, ranging from stress relief, through the reinforcement of happiness and the improvement of energy, focus and motivation down to the creation of feelings of deep attachment.,
Regrettably, sex does not only have benefits. Given the natural character of this activity, it is difficult to speak of it in terms of costs. Other than physical energy and the money paid for protection, lovers do not really have to “spend” anything when enjoying their time together this way. That being said, there are downsides to intercourse, which should rather be regarded as risks rather than as costs. First and foremost, a woman always faces the possibility of getting pregnant. If she does not want the baby, she has to find a way to free herself from the burden. Many solutions to this “problem” can have profound consequences on both her physical and emotional well-being as well as on other aspects of her existence (including her reputation, career, lifestyle, etc.). Then, by sleeping with someone, we expose ourselves to the other’s illnesses, in particular, his or her sexually transmitted diseases (HIV, genital herpes, gonorrhoea, syphilis, human papillomavirus / HPV, among countless others). Barrier devices such as condoms, dental dams, or gloves can significantly reduce the risk of infection. Nevertheless, one should be aware that no protective device or technique is ever entirely safe and that some peril always remains. From there on, it is merely a mathematical truth that the more sexual partners a person has, the higher the probability of contracting an STD.
 Diamond (1998), p. 69
 Kearns (2008), p. 223
 Vartan (2012)
 Hatfield (2014)
 See chapters 28 “Pluck flowers as they bloom; wait and you’ll have only the twigs”, 30 “You can’t help shoots grow by pulling them up higher”, and 32 “Hearing something one hundred times is not as good as seeing it once”.
 Pease / Pease (2009), p. 250
 Meston / Buss (2009), pp. 252-253
 Fisher (2010), pp. 219-220