AI drives 10-fold growth in Japan's extramarital dating over three years, Cuddle membership surpasses 1 million

Mrs. Watanabe, an economics term unique to Japan, may be heading toward extinction in the 21st century. Because the family unit that sustains it is tending to disintegrate.

Over the past three years, thanks to rapid advances in AI technology, the number of active users of Japanese extramarital affair social apps has grown nearly tenfold, and penetration among young people aged 30-40 has already reached 5%.

Japan's marriage system is undergoing an unprecedented shock.

Some sociologists say that the "free love + monogamy" marriage established in the 20th century had as its historical function the packaging of sex, emotion, economic cooperation, child-rearing and elderly care into a lifelong contract. This packaged arrangement was efficient under specific historical conditions (women's economic dependence, shorter lifespans, low social mobility).

But with the arrival of the era of economic globalization, women's labor force participation rate has risen, and marriage is no longer the only channel for women to obtain economic security; the sex industry has been legalized or semi-legalized in many countries, decoupling sex from reproduction and from marriage; AI technology has greatly improved the matching accuracy and concealment of extramarital affair social apps; and the DINK and declining birthrate trends had already decoupled reproduction from marriage.

The marriage system has not been abolished, but it has been "unbundled" in function. When sex, emotion, economy and child-rearing can be obtained separately, marriage changes from "a container that satisfies all needs" into "an option, and one that no longer has to satisfy all needs." The rise of Japan's extramarital affair app market is precisely the commercial expression of this "unbundling" process: it does not attack marriage, it merely takes on the portion of needs that the marriage container is no longer willing or no longer able to take on.

(Cuddle official website)

Japan's galloping extramarital affair social boom

If you travel to Japan during this period, when passing through Shibuya or Shinjuku, you will most likely see advertisements for dating apps "exclusively for married people" on outdoor billboards.

This was an unimaginable sight a few years ago.

Today, Cuddle, Healmate and Kikonsha Club, three platforms, form the "big three" of this track, and the three are fighting fiercely. Among them, Cuddle, which has made the loudest AI narrative, is precisely the epitome of this round of growth.

Cuddle launched in February 2022 and introduced an AI matching system in 2024, since when it has entered a period of rapid growth. It is reported that Cuddle had 400,000 members in September 2024, surpassed 700,000 in July 2025, adding 300,000 in 10 months, with average daily registrations approaching 1,000; by December 2025, the official figure for cumulative members exceeded 1 million, and third-party estimates by 2026 have reached about 1.3 million.

Cuddle publicly claims that its AI system facilitates a match on average every 4 seconds, and efficiency is the main driver of this round of growth.

At present, the nominal cumulative account numbers of the big three can reach up to about 2.8 million, accounting for 4.4% of Japan's 64 million married population.

Unlike the previous round of stranger social products, which used large numbers of bots to induce male users to pay, extramarital affair apps represented by Cuddle play it real, that is, focusing on "feasibility matching" of real users. The platform strictly reviews the authenticity of user identities. Cuddle says that through its AI anti-fraud system it claims to be able to identify scammers, marketing accounts and accounts with "abnormal purposes" in real time, and plans to introduce Japan's My Number Card for identity verification, ensuring that everyone is in a pure circle of married people's games.

What AI focuses on solving in this scenario is the efficiency of "feasibility matching." Before AI technology matured, extramarital affair matching was a costly algorithmic engineering task: a full-time housewife might only be free on weekday daytime after the children go to school, while an office worker might only have an hour or two at lunch break or before getting off work. How to complete the complex matching of suitable candidates within this limited window period was previously an impossible project.

Through AI, Cuddle has users register whether they have children and the time slots convenient for meeting, then combines behavioral data such as login frequency and reply intervals, and even identity IDs, to predict when two people are simultaneously in an available state. It can even use natural language processing to understand colloquial descriptions such as "convenient during the days when my husband is on a business trip." On the tech stack, Cuddle claims to use LSTM and Transformer to learn users' activity patterns, NLP to analyze the emotional tendency of chats, graph neural networks to analyze relationship structures, and reinforcement learning to optimize matching strategies. Under the traditional approach, the entire chain of "probing—negotiating—finding excuses" is compressed into a single push, and matching becomes precise and efficient.

(Security is the survival foundation of every extramarital affair app)

If Cuddle is an AI-driven efficiency platform, then Healmate uses the narrative of a "second partner" and spiritual communication, leaning more toward search and community, while Kikonsha Club retains a bulletin-board-style mode in which users actively seek. AI is a growth engine for Cuddle, and for the other two it is more about back-end risk control and assistance.

The three share one premise: married people need a low-friction matching space that cannot be seen by their spouses.

When we discuss extramarital affairs, we are discussing more than sex

As a country where the sex industry is semi-legalized, the commodification of sex in Japan became widespread as early as the previous 100 years. Whether it is soap lands and papa-katsu for male consumers, or host clubs for female consumers, buying sex is as simple as buying a bottle of mineral water at a convenience store.

So why are some people still willing to pay, spend time and bear the risk of exposure on a platform with uncertain results, in pursuit of a chance that may not even "get to first base"?

Because the sex industry sells certainty of release, while extramarital affair apps sell the experience of being actively chosen by a subject who also has desires. The former is a transaction: I pay, the other party provides a service, and the relationship ends once the transaction is complete. The latter preserves the entire emotional sequence of pursuit, probing, waiting for a reply, being rejected or accepted. A Japanese man who had long frequented "papa-katsu" once described it as "after all, an interaction mediated by money, and somewhere along the way you feel empty"; after turning to a married-person app, what he felt was "the kind of satisfaction of recalling love when I was young." Certainty can be bought with money, but the uncertainty of "being chosen" is precisely what the sex industry structurally cannot deliver.

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This structure of demand also explains changes in the user age profile. Cuddle's core users are married people in their 30s and 40s, over 60% of whom have children. But middle-aged and older groups are entering this market. A survey by MMD Research Institute shows that among people in their 50s, 19.3% have experience using matching apps. For the 50+ population whose children are independent, who are nearing retirement or have already experienced a "graduation from marriage"-style loosening of relationships, the sexual and emotional functions of marriage may long have existed in name only, yet the need to "be seen" does not disappear with age.

Cuddle even stated that the company is currently researching the LGBTQ market and does not rule out launching products targeting them.

Changes in human society: formally moving from the era of construction to the era of deconstruction

If the 20th century was an era of construction, then the 21st century is an era of deconstruction.

In the early 20th century, human society overthrew the decadent feudal hierarchy, established free love and a new marriage system, and popularized free work and the right to free elections.

In social cell theory, the family is regarded as the smallest cell of society, and marriage is the metabolism of new cells. The marriage system of the 20th century was essentially a packaged container: sex, emotion, economic cooperation, child-rearing, and elderly care were bundled into a lifelong contract. Over the past half century, each function of this container has been unbundled one by one:

(1) Women's labor force participation has risen, and marriage is no longer the only channel for women to obtain economic security;

(2) The sex industry has been legalized or semi-legalized in many countries, unbundling sex from reproduction and from marriage;

(3) AI technology has greatly improved the matching accuracy and concealment of extramarital socializing;

(4) And DINK and declining birthrates have already unbundled reproduction from marriage.

(Poster of a host club on a Japanese street)

Japanese sociologists have observed that since the 21st century, "the functions contained in marriage are being provided individually," and the emergence of forms such as cohabiting divorce, friendship marriage, and second partners points in the same direction: marriage is changing from a "default container" to "one of the options."

Business plays a dual role in this process. As a release valve, it may delay the breakdown of marriage: some users explicitly state that after finding a "second partner," they no longer make demands on their husbands, and the marital relationship has instead become more harmonious. If this model holds on a larger scale, then the social function of such platforms is not to dismantle marriage, but to allow marriage to be maintained even when it does not satisfy all needs.

But as an accelerator, it is changing people's expectation structure for marriage: when supplements for emotion and sex can be subscribed from outside at any time, marriage contracts from an "emotional community" toward a "life cooperation framework," and people's expectations that these needs will be satisfied within marriage will decline. What is truly unsettling is not that "desire is commercialized," but that business is beginning to systematically take over the relationship functions originally guaranteed by "commitment" and "exclusivity."

Future social structures are more likely to trend toward a stratification of relationships. The marriage layer retains legal, economic, child-rearing, and elderly-care functions, but the expectation of exclusivity in emotion and sex continues to weaken, making it increasingly like a life cooperation contract. The emotional layer is taken over by commercial platforms: subscribable, exitable, low-commitment, strong privacy. The sexual layer in legalized societies has long been highly commercialized and separated from emotion, while extramarital affair apps repackage sex and emotion into an intermediate zone that is "project-based, renewable, and low-exposure-risk." Each layer solves one specific problem, and no layer tries to solve all problems. Efficiency is higher, but the connections between layers are fragile.

This stratification also brings a new inequality: emotional supplementation exists only as a service with a payment threshold.

One phenomenon that cannot be ignored is that among the above three extramarital social platforms, male users with stronger payment ability are the currently dominant version—they are presidents, executives, doctors, lawyers, and other high-paying professions. The logic is simple: the high monthly fee itself screens for payment ability; and to play this illicit emotional game, they also need to spend more to win over the characters, just like in Japanese AVG games.

These platforms inevitably become hunting grounds for high-class men, which runs counter to the liberalism promoted by the platforms.

This article comes from the WeChat public account "Needle Point," author: doing this at a young age, published by 36Kr with authorization.