Unreasonable behaviour is the workhorse of Singapore divorce law. It is the most commonly cited fact because it does not require a waiting period, a confession or a private investigator, only a truthful account of conduct that made the marriage unliveable for you.

But “unreasonable behaviour” is often misunderstood. It is not a general complaint that your spouse was unreasonable; it is a specific legal test with a track record of what does and does not persuade the Family Justice Courts. This guide sets out the test, concrete examples that count, the evidence that helps, and the common mistakes that weaken a case.

Under section 95A of the Women’s Charter 1961, you must show that your spouse “has behaved in such a way that [you] cannot reasonably be expected to live with [them]”. Strictly speaking, the law does not ask whether the behaviour was unreasonable; it asks whether it is unreasonable to expect you to go on living with your spouse because of it.

The courts apply a mixed test: would a right-thinking person, looking at this particular plaintiff and this particular defendant, with their characters, personalities and history, conclude that the plaintiff cannot reasonably be expected to live with the defendant? Two consequences follow. First, the same conduct can succeed in one marriage and fail in another, because context matters. Second, the cumulative effect counts: a long pattern of smaller incidents can satisfy the test even if no single incident is dramatic. Unreasonable behaviour is one of six facts proving irretrievable breakdown (the sole ground for divorce), and you can compare all of them in our guide to the grounds for divorce in Singapore.

Unreasonable behaviour examples that count

There is no fixed list, but successful cases tend to fall into recognisable categories.

Financial irresponsibility

Chronic gambling, hiding significant debts, refusing to contribute to household expenses despite being able to, draining joint savings without agreement, or borrowing from loan sharks. Money-related conduct is one of the most commonly pleaded categories.

Violence, threats and abuse

Physical violence, threats of harm, and sustained verbal or emotional abuse: humiliation, intimidation, gaslighting. Where there has been family violence, a personal protection order (PPO) application may run alongside the divorce, and PPO records strongly support the fact.

Addiction

Alcohol or drug abuse, and gambling addiction, especially where it led to broken promises to seek help, financial harm or frightening behaviour at home.

Neglect and absence

A spouse who is perpetually absent without explanation, prioritises work or friends to the point of abandoning family life, refuses intimacy or communication for prolonged periods, or leaves the plaintiff to raise the children and run the household entirely alone.

Improper association and infidelity short of provable adultery

Secretive, intimate relationships with a third party (late-night messaging, dating-app activity, unexplained hotel charges) pleaded as an “improper association”. This is the standard route when an affair is suspected but sexual intercourse cannot be proved to the high standard the adultery fact requires. You do not need a PI report to plead improper association.

Controlling and isolating behaviour

Monitoring the plaintiff’s phone and movements, controlling all money and requiring receipts for basic spending, cutting the plaintiff off from family and friends, or dictating how they dress and whom they see.

What evidence helps

If your spouse does not contest the divorce, which is the majority of cases, your own truthful account in the court papers is usually sufficient, and the case can proceed on the simplified track. See how an uncontested divorce works.

If the fact is likely to be disputed, contemporaneous records carry the most weight:

  • Text and chat messages, emails and call logs
  • Police reports, PPO applications and medical reports for violence or threats
  • Bank and credit card statements showing gambling, debts or dissipation
  • Photographs, and statements from family members or helpers who witnessed incidents
  • A dated personal record of incidents kept as they happened

How much detail does your statement need?

The particulars filed with your originating application must move beyond labels to specifics. “The defendant was verbally abusive” is a conclusion; what persuades is “in around March 2024, during an argument about the defendant’s gambling, the defendant called the plaintiff [specific words] in front of the children”. A well-drafted statement typically covers the first significant incident, the worst incident, the most recent incident, and enough of the pattern in between to show the cumulative picture, each with approximate dates.

One timing rule to know: the law disregards short periods of continued cohabitation, up to six months in total after the last incident relied on, so attempting reconciliation does not automatically undermine your case. Living together long after the conduct ended, however, can. If you are weighing when to file, our guides on preparing for divorce cover the practical groundwork.

Common mistakes to avoid

  • Vague, sweeping allegations: “he was cold and difficult” with no incidents, dates or context gives the court nothing to act on.
  • Exaggeration: inflating incidents invites a contest, damages your credibility, and can turn a straightforward divorce into a long fight over the marriage’s history.
  • Kitchen-sinking: listing every grievance from a decade of marriage buries the strong points. A focused statement of the serious, representative incidents works better.
  • Relying on one trivial incident: a single forgotten anniversary or one heated argument will not, alone, satisfy the test.
  • Needless aggression when agreement is possible: many couples negotiate the wording of the behaviour particulars so the defendant will not contest. Milder, agreed particulars that still meet the test get you divorced faster and cheaper than a maximalist draft that provokes a defence.

Unreasonable behaviour vs the other facts

Compared with the alternatives, unreasonable behaviour is immediate: you do not need to wait out three or four years of separation, prove intercourse as adultery requires, or secure your spouse’s agreement as divorce by mutual agreement does. That immediacy is why it remains so heavily used even after mutual agreement became available in July 2024.

Its drawback is that it involves criticising your spouse on the court record, which can sour negotiations over children and assets. If your spouse is cooperative, divorce by mutual agreement or separation-based facts may keep things more amicable; if you have proof of an affair and want to plead it, see our guide to adultery and divorce in Singapore. Whichever fact you choose, the fact only opens the door: custody, maintenance and asset division are decided separately in the divorce process, and citing worse behaviour does not generally buy a better financial outcome.

Further reading