The institutional separation of sex and marriage before modernity

Across most of Japanese history, romantic feeling, sexual relationship, and marriage as a social and economic bond were never automatically unified in one relationship. In the Edo period especially, marriage functioned less as personal fulfillment than as an economic and status-based arrangement serving the continuity of the household. The pleasure quarters — licensed and regulated by the shogunate and regional domains — filled a separate role, as spaces for sexual desire and emotional companionship. Courtesans there were never simply objects of transaction; they were expected to carry real cultivation, artistry, and conversational skill, and relationships with clients unfolded through an established, almost ceremonial protocol. Under this arrangement, a marriage that also happened to involve romantic love was the exception rather than the rule — and when the two aligned too intensely outside sanctioned bounds, it could end in something as extreme as a double suicide.

The modern arrival of “romantic love ideology”

Following the Meiji era, as Western ideas of the modern family took hold, a new ideology arrived that fused romance, sex, and marriage into a single unit. It didn’t actually become the dominant social norm in Japan until sometime between the late 1960s and the 1970s. Once the model — falling in love with one fated person, deepening intimacy, and sealing that bond permanently through marriage — became the accepted standard, anything outside it, whether sex without romantic attachment or romance outside marriage, was pushed to the margins as an ethical lapse.

“Friends with benefits” versus the historical courtesan relationship

Today’s “friends with benefits” arrangement might look, on the surface, like the historical pleasure-quarter relationship — sex without romantic feeling attached — but the underlying structure and psychology are fundamentally different.

The modern FWB dynamic is a genuinely new phenomenon, emerging from the free dating market, matching technology, and the gradual relativizing of romantic love ideology itself. It’s best understood as a transitional kind of relationship: individuals, freed from institutional pressure, trying to meet physical need and loneliness while sidestepping both the risk and the responsibility that real intimacy carries.

The psychology of Ōba Yōzō

Osamu Dazai’s No Longer Human traces, in unflinching detail, how desire, loneliness, the hunger for approval, and self-loathing tangle together and pull a person toward relationships that ultimately destroy them. At the root of the protagonist, Ōba Yōzō, sits a fear of other human beings and an isolating sense that he is fundamentally different from everyone around him. To hide this, he adopts what the text calls “clowning” — an exaggerated strategy of preemptively performing what others expect of him, both to avoid attack and to win a counterfeit kind of acceptance.

For Yōzō, sex functions less as a pursuit of love than as an escape from existential dread. In every relationship he enters, he remains passive, essentially parasitic on the maternal warmth the women around him offer. A woman’s body and affection become, for him, a temporary shelter from a terrifying human world. But every relationship he forms ends up wounding both parties and ultimately drives him toward ruin. His pathology follows a specific self-destructive logic: he craves approval, but fear of rejection keeps him from ever revealing his true self, so he falls back on temporary, compensatory emotional and sexual bonds — bonds that only deepen the self-loathing that started the cycle in the first place.

A literary lineage of self-destructive attachment

The theme of wanting love and approval, and then choosing precisely the relationships that will wound you, recurs across world literature. In Sōseki Natsume’s Kokoro, “Sensei” carries such deep guilt over betraying a close friend that he holds his own wife at an emotional distance even while loving her deeply, effectively imprisoning himself in psychological isolation. In Dostoevsky’s Notes from Underground, the narrator’s crushing pride and hyper-self-consciousness make a healthy relationship impossible; when a prostitute named Liza offers him genuine tenderness, he wounds her with a display of superiority and rejects her love outright, sealing his own loneliness for good. What these works share is a kind of moral perversity of feeling: a deep human wish for connection and approval that, precisely because of a fear of one’s own imperfection and vulnerability, produces choices that end up dismantling the self instead.

Attachment style and sexual behavior

Attachment theory offers one of the strongest frameworks available for understanding adult romantic and sexual behavior. Securely attached people carry high self-worth and trust in others, and tend to deepen sexual intimacy while balancing closeness with genuine independence. Anxiously attached people, driven by a strong fear of abandonment, often try to compensate for low self-regard through others’ approval — they frequently conflate love with sex, using physical closeness to manufacture a sense of emotional unity. Avoidantly attached people, distrustful of others at a basic level, actively avoid the vulnerability that real emotional closeness demands — they gravitate toward emotionally detached casual sex or short-term relationships with multiple partners, treating sex as stress relief or a physical need rather than a path toward intimacy.

Sex as emotional regulation, and where gender enters

Sexual behavior doesn’t only satisfy physical desire — it can also function as a form of self-compensation, suppressing or regulating loneliness and low self-efficacy. Impulsive sexual behavior undertaken specifically to soothe an uncomfortable feeling tends, afterward, to produce real regret and guilt. A gender gap shows up here consistently: women report higher psychological regret after casual sex than men do, a pattern that reflects not only the asymmetric biological risk of pregnancy but the ongoing double standard applied to women’s sexual autonomy, which adds its own separate psychological weight.

Temporal discounting and the mechanics of regret

Behind the pattern of choosing momentary pleasure and regretting it later lies a mechanism from behavioral economics known as temporal discounting — the cognitive bias of overvaluing a small reward available right now over a larger reward available only in the future. When prefrontal self-regulation is insufficient, or when stress or alcohol impairs the brain’s inhibitory systems, people fall into hyperbolic discounting: the value of an immediately available desire spikes disproportionately, while the real future cost — regret, a damaged relationship — gets pushed almost entirely out of view.

Rusbult’s investment model

Caryl Rusbult’s investment model of commitment offers a robust framework for understanding what actually keeps relationships intact and prevents impulsive infidelity.

Once commitment reaches a high enough level, several self-sustaining maintenance mechanisms kick in automatically: accommodation (responding to a partner’s misstep constructively instead of retaliating), willingness to sacrifice one’s own interest for the relationship, forgiveness of past wrongs, positive illusions that idealize a partner’s strengths, and actively derogating attractive alternatives outside the relationship. Rusbult’s research suggests that staying devoted is rarely about feeling no temptation at all — it’s that accumulated investment and commitment actively engage these cognitive biases, neutralizing the pull of the alternative before it can gain traction.

How aging and parenthood shift values

Developmental psychology explains why people, after aging or becoming parents, often look back on their younger, more impulsive behavior as foolish. Erik Erikson’s stage theory frames early adulthood’s central task as intimacy versus isolation, but describes that task shifting, in midlife, toward generativity versus stagnation. Laura Carstensen’s socioemotional selectivity theory shows something similar: as remaining time in life starts to feel finite, people’s preferences narrow toward a small number of deep, high-quality relationships rather than broad exploration. Becoming a parent tends to trigger a real cognitive reappraisal — the self-concept expands from “the one pursuing momentary desire” to “the protector of someone genuinely vulnerable.” Seen through that lens, choices once rationalized as youthful freedom get reconstructed as real risk — emotional harm, real vulnerability exposed — producing the retrospective judgment: that was a foolish choice.

Instinct versus social and ethical learning

Is devotion to one person a biological instinct, or a product of social learning? The human sciences today land somewhere in between: devotion is not a simple instinct, but a higher-order ethical and volitional choice built on top of an evolutionary foundation. Humans are not a strictly monogamous species — we carry a strong tendency toward pair-bonding alongside a flexible mating strategy that, given the opportunity, also pursues extra-pair mating. Feeling drawn to someone other than your partner is, in itself, a perfectly natural response wired into the brain’s reward system. What we call devotion, then, is not the absence of that pull — it’s the psychological capacity to govern a biological impulse through internalized social norms.

Ethics and psychology alike rate the second, active form of devotion more highly. It’s impossible to fully control the feeling of attraction to someone else — but it is entirely possible to choose how to act on that feeling. The real substance of devotion isn’t suppressing sensation; it’s the repeated, willed re-choosing of a relationship one has already decided matters.

Kierkegaard and Frankfurt

The Danish philosopher Søren Kierkegaard divided human ways of living into an “aesthetic” stage and an “ethical” stage. The aesthetic stage is governed by desire, momentary sensation, and the pursuit of novelty; because someone chasing the moment can never build a continuous, lasting identity, that stage ends, inevitably, in despair. The ethical stage accepts responsibility and commitment — and its emblem is marriage. Ethical marriage, in this frame, doesn’t reject aesthetic romantic feeling; it is the willed act of making a fleeting aesthetic moment eternal, a repeated decision — “I will live with this person” — made again and again inside a future that remains genuinely unpredictable.

The contemporary philosopher Harry Frankfurt, in The Reasons of Love, describes love as a kind of volitional necessity. To genuinely care about something, on his account, means constraining one’s own fickle first-order desires — the pull toward someone new, the wish to play — with a higher-order will, and binding oneself to that object. It is only by placing oneself under this kind of chosen unfreedom that a person achieves real identity and genuine autonomy.

The idea that a psychologically mature person simply doesn’t feel desire is false. Maturity isn’t the disappearance of desire — it’s a transformation in one’s relationship to it.

Psychological maturity refers specifically to Type 3 — the value-integrated, relativizing type. Someone in this state genuinely feels sexual desire and attraction to someone new, but can weigh it against what they’ve already identified as their most important relationship, treating the present impulse as comparatively small.

Devotion is genuinely difficult for human beings because our very structure carries layered, competing contradictions. Biologically, two opposing mechanisms are wired in at once: an interest in a variety of sexual partners, which helps secure genetic diversity for the species, and strong pair-bonding with one specific partner, which supports raising a helpless infant over years. Psychologically, unresolved attachment anxiety and loneliness create a pull toward quick fixes — validation from others, momentary sexual connection — as an easy patch. And existentially, no matter how deeply two people bond, each person remains, at bottom, unavoidably alone; the fear of that solitude can push people toward consuming others, or toward relationships too fleeting to mean anything, simply to dull the fear.

And yet people also possess something else: the capacity for mental time travel — reflecting on the past, vividly imagining an uncertain future, and relativizing a present impulse against that much larger timescale. Living devotedly does not mean no longer feeling temptation. It means recognizing, honestly, that the desire to find someone else attractive genuinely exists within you — and choosing, again, based on your own values, to keep the relationship you’ve already decided matters. It’s that repeated act of choosing that slowly accumulates what Rusbult calls investment — shared memory, trust, history — into a bond sturdy enough to withstand a single gust of feeling.

Four hypotheses about psychological maturity