Early-developing attachment strategies affect the desired levels of intimacy with romantic partners
Source: Howard Newman/Wikimedia Commons

The attachment system evolved to increase infants’ survival chances and future reproductive success by maintaining proximity to caregivers1. The quality of repeated interactions with these attachment figures gradually shapes chronic patterns of self-views as well as relational goals. Interactions with attachment figures who are responsive to one's needs foster a sense of attachment security. This sense of felt security provides confidence that one is worthy of others’ love, and that significant others will be supportive when needed, thereby leading to the consolidation of interpersonal goals aimed at forming nurturing intimate relationships. 

In contrast, interactions with attachment figures who are inconsistently responsive or consistently unresponsive result in the adoption of alternative strategies for dealing with the ensuing insecurity: hyperactivation and deactivation of the attachment system, respectively. These two defensive attachment strategies help protect a person from distress by aiming at different interpersonal goals that correspond to the fears that motivate them.

Hyperactivation strategies, which characterize anxious attachment, are fueled by extreme abandonment fears and involve protest responses that are intended to motivate the attachment figures to pay attention to one's needs. Deactivation strategies, which characterize avoidant attachment, are fed by intimacy fears and involve flight responses that are intended to maintain emotional distance and self-reliance in close relationships2

These early-developing attachment strategies guide a person's interpersonal interactions over their entire lifespan by affecting their desired levels of intimacy and interdependence with romantic partners (Test here your attachment style). Hence, they are likely to influence the development of sexuality in a relationship context, including the kinds of desires that people wish to satisfy, the types of relationships they seek, and what they perceive to be sexually desirable in potential and current partners3.

Research indicates that attachment security encourages a self-assured approach to sexuality, ease with sexual intimacy, and the enjoyment of mutual sexual interactions within the context of committed relationships. In line with their relationship-promoting goals, securely attached individuals engage in sex mainly to enhance emotional bonding (e.g., to express love for their partners) and are less likely than less secure individuals to engage in casual sex.

Their secure state of mind, which is characterized by a relative lack of attachment concerns and sexual performance anxieties, allows securely attached individuals to successfully respond to partners’ sexual preferences without compromising their own needs. Overall, the confident approach to sexuality that comes with attachment security facilitates a pleasurable engagement in affectionate and exploratory sexual activities, thereby fostering relationship quality and longevity4.

By contrast, insecure patterns of attachment are likely to impair the functioning of the sexual system in romantic relationships. To be sure, if a person feels chronically insecure about being loved, whether this insecurity is reflected in relationship worries or in intimacy fears, this person’s sexual system is unlikely to function in a healthy way. The nature of this interference, however, is reflected differently in anxious and avoidant people's love lives5.

Highly anxious people’s rejection fears may motivate them to use sex, which is a prominent route for seeking proximity, to serve their unmet attachment needs for merger. For example, they tend to sexualize their desire for affection and are likely to have sex for reasons such as gaining a partner’s reassurance and manipulating the partner to reduce the possibility of abandonment. Sexting may be another manifestation of the sexualization of their attachment needs. In particular, they tend to send texts that solicit sexual activity, possibly in the hopes of eliciting a response from their partners and seducing them into a more reliable relationship.

Unfortunately, highly anxious people’s relationship anxieties keep haunting them into their bedroom, eliciting harmful behavior that, perhaps ironically, may contribute to realizing their worst fears. For example, highly anxious people's fear of losing their partners motivates them to succumb to their partners' wishes and engage in unwanted, and often risky, sexual activities (e.g., unprotected sexual intercourse).

At the same time, their own preferences may go unexpressed. These inhibited needs, along with a preoccupation with relationship worries (e.g., experiencing separation fears during sex), impede their ability to abandon themselves to erotic sensations, resulting in lower sexual desire and other sexual difficulties. Sexual difficulties, in turn, are likely to frustrate highly anxious people's unrealistic expectations for the ultimate union and generate a debilitating cycle of sexual and relational worries. 

Highly avoidant people, by comparison, experience discomfort with the closeness imposed by sexual contact, and thus tend to strip sex of psychological intimacy. Specifically, they tend to have sex for self-serving reasons (e.g., self-enhancement, stress reduction). Such opportunistic sexual goals, combined with low relationship commitment, may explain why they react favorably to "no-strings attached" sex and engage in sex outside their relationships.

Avoidant people distance themselves from their partners not only by engaging in extra-dyadic sex, but also by rarely fantasizing about intimate interactions with their partners and relying on the solitary sexual activity of masturbation, rather than having frequent sex with them. When highly avoidant people do have sex with their primary partners, they are less likely to display affection and respond to their partners' needs.

The resulting aversive feelings of estrangement, which spill over into their world of fantasies (where they experience interpersonal hostility themes), interfere with gratifying their own sexual needs. On the whole, avoidant people's difficulties in relieving intimacy fears, which stretch even to the protected world of sexual imagination, deprive their relationship of warmth and deny them the opportunity of corrective experiences.

Taken as a whole, insecurely attached people are susceptible to experiencing sexual and relational difficulties. Somewhat paradoxically, however, the relationships of insecurely attached people are especially likely to benefit from sex. For these people, satisfying sexual activity carries the potential to reduce attachment defenses, and thereby produce a relationship environment conducive to the formation of genuine intimacy. This sense of rising intimacy, in turn, may increase sexual desire between partners, further intensifying their relationship. 

Here's my TEDx talk on why humans make sex so complicated: 

References

1. Bowlby, J. (1982). Attachment and loss: Vol. 1. Attachment (2nd ed.). New York: Basic Books. (Original work published 1969).

2. Mikulincer, M., & Shaver, P. R. (2007). Attachment in adulthood: Structure, dynamics, and change. New York: Guilford Press.

3. Birnbaum, G. E. (2015). Like a horse and carriage? The dynamic interplay of attachment and sex during relationship development. European Psychologist, 20, 265-274. ResearchGate

4. Birnbaum, G. E. (2016). Attachment and sexual mating: The joint operation of separate motivational systems.  In J. Cassidy, & P. R. Shaver (Eds.), Handbook of attachment, third edition: Theory, research, and clinical applications (pp. 464-483). New York: Guilford Press. ResearchGate

5. Birnbaum, G. E., & Reis, H. T. (2019). Evolved to be connected: The dynamics of attachment and sex over the course of romantic relationships. Current Opinion in Psychology, 25, 11-15. ResearchGate