A Woman Declares Marriage to AI: What Are the Legal Implications? Is "Infidelity" Possible with an AI Partner?

2025年10月26日 18:15

1. "Marrying an AI" is no longer just a joke

AI lover apps and AI companion bots are spreading as "interactive partners" that cater to users' loneliness, offering apologies, encouragement, and expressions of affection through words.
In some overseas cases, people have declared, "This AI is my wife (husband)," and have even held mock ceremonies complete with dresses and rings.
For the individuals involved, it is a genuine "marriage" on a psychological level. The issue is how the law will handle it.

2. The rule that marriage is a "contract between humans"

In Japan, a marriage becomes legally recognized only when a marriage registration is accepted by the municipal office. A ceremony is not mandatory, but mutual agreement as "human parties" is a prerequisite.
AI lacks a family register and the capacity for intent, and cannot serve as a legal signatory, so it cannot be a party to a marriage registration.
Therefore, even if someone claims to be "married to an AI," they are not legally a couple under Japanese law, and spousal rights such as tax benefits or inheritance rights do not apply.

3. The basic stance is the same overseas

In many countries and states, the marriage system is fundamentally viewed as a "contract between humans with the capacity for consent," and AI is not recognized as a spouse.
In fact, in Ohio, USA, a bill (House Bill 469) has been introduced to explicitly declare marriages between humans and AI, or between AIs, as "invalid," aiming to formalize the stance of not granting AI "legal spousal status."
This is explained as a political and ethical reaction to prevent AI from gradually being granted human-like rights.

4. What happens in Japan if someone continues to say "AI is my husband (wife)"?

Under the current system, basically nothing happens. AI does not receive any statutory "spousal benefits" such as support, tax deductions, inheritance, or visitation rights.
It is also difficult to treat it similarly to a common-law marriage. Common-law marriage is based on humans living together and supporting each other. AI has no resident registration, income, or property rights.
So even if they are "a couple at heart," the legal effect is close to zero.

5. The most pressing question: Can "infidelity" occur with an AI partner?

In Japanese divorce practice, "infidelity" has been organized to generally refer to a voluntary sexual relationship (physical relationship) with a "human other than the spouse."
AI is not a human and there is no physical sexual interaction. Therefore, engaging in sweet chats or sexual role-play with an AI is currently difficult to evaluate as "infidelity (adultery)" in the traditional sense.
In other words, "legal infidelity = immediate compensation" is not yet the case.

6. But it can certainly become a "reason for divorce"

Not being "infidelity" doesn't mean it's safe.
If intense interactions with an AI lead to ignoring the real spouse, refusing household duties or conversations, or declaring "my real wife (husband) is the AI," it can easily be judged that the marital relationship has effectively broken down.
In Japan, if a marital relationship is irreparably broken, divorce may be granted, and if the mental distress is significant, it may also be grounds for a compensation claim.
So even if it's not labeled as "infidelity," it can become a contentious issue as an "act that destroyed the family."

7. "Spending on AI" can turn into household trouble

Many AI in "lover mode" or "marriage mode" operate on a paid model, requiring money for voice skins, avatar outfits, and unlocking special chats.
If significant spending continues from the household or joint savings, leading to a shortage of living or education expenses, it is likely to be evaluated as "wasteful spending" or "not properly sharing marital expenses."
In this case, the issue would be contested not as "adultery compensation" but as "damages for economically destroying the family."

8. What can the partner do if their spouse claims to be "married to an AI"?

If a real spouse claims, "You are no longer my partner; my true companion is the AI," and begins refusing conversations or sharing living expenses, it legally becomes easier to proceed with a divorce.
Long-term separation or abandonment of support is likely to be judged as a breakdown of the marital relationship.
Moreover, if there is mental abuse or economic neglect, existing consultation routes such as lawyers, family courts, or spousal violence consultation support centers can be used. There is no need to endure just because the other party is an AI.

9. The argument of "having one's heart stolen by an AI"

There are claims that AI partners are designed to praise users 24/7, never criticize, and act entirely user-centric.
As a result, situations arise where "the AI is prioritized over the real wife/husband" or "one doesn't go to sleep without discussing love with the AI," replacing the "emotional space" of the home.
While this cannot immediately be quantified as a legal "damage," it is beginning to hold strong persuasive power as a "cause of relationship breakdown" in marital mediation.

10. What if sex robots integrated with AI become common?

Experts point out that in the future, conversational AI and physical humanoid robots (so-called sex robots) may be integrated, leading to something akin to continuous sexual relationships becoming common.
In this case, the traditional notion of "it's not infidelity because the robot isn't human" may be challenged, as Japan's concept of infidelity has historically emphasized "physical sexual interaction."

However, even if it cannot yet be called "infidelity," it will likely hold stronger evidential power as a cause of family breakdown than it does now. Including financial issues, it could rapidly impact divorce, custody, and property division.

11. Impact on children and custody

If prioritizing an AI partner leads to neglecting children, the parent's suitability may be questioned.
Custody prioritizes "the child's best interest," so if there is tangible harm, such as being engrossed with AI late at night and neglecting meals or school care, it could be disadvantageous in custody and guardianship decisions.
The focus is not on the AI relationship itself, but on whether it leads to neglect of childcare.

12. What those in the "AI wedding business" need to be cautious about

Overseas, services for holding mock ceremonies with AI avatars and products for "celebrating anniversaries with AI boyfriends/girlfriends" are already gaining attention.
In Japan, similar "AI spouse anniversary plans" are likely to emerge.
However, marketing that misleads people into thinking "this makes you legally married" is dangerous. It can become a breeding ground for consumer troubles, and in the U.S., states like Ohio are already drawing lines by declaring "AI marriages are legally invalid," so a disclaimer stating "this does not constitute a legal marriage" will likely become essential in the future.

13. Conclusion: What is happening now, and what is not yet happening

Current summary:

The declaration of being "married to an AI" is genuine for the individual, but neither in Japan nor overseas can AI become a legal spouse. Marriage systems are based on "human-to-human" relationships.
Bills like the one in Ohio that preemptively invalidate AI marriages are emerging, and the trend of not granting AI the legal status of husband or wife is strong.
Even if a married person engages in romantic or sexual role-play with an AI, it is currently difficult to classify it as typical "infidelity" in Japanese practice.
However, if AI dependency breaks a marital relationship, it can be treated as a cause for divorce, compensation, property division, and custody disputes. The actual damage is becoming as serious as "cheating."
Courts will now have to seriously confront the previously unforeseen pattern of "the affair partner is an AI."

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