When "I Do" Undoes a Will: Marriage, Capacity, and the Intestacy Trap

Most Australians understand that a Will needs to be updated when major life events occur. Fewer understand that a single event, marriage, automatically revokes any existing Will by operation of law, regardless of its content, regardless of how recently it was made, and regardless of whether the person who married intended that outcome.

For most couples, this is a manageable inconvenience: they update their Wills after the wedding and move on. But for a growing number of vulnerable people, particularly older Australians with cognitive decline it is a legal mechanism that can strip an entire estate from intended beneficiaries and deliver it instead to a new spouse, sometimes after a marriage of days or weeks, and sometimes in circumstances that the person who married did not have the capacity to fully understand.

The Australian Government has recognised the seriousness of this problem. From 12 June 2024, all authorised marriage celebrants in Australia are required, by amendments made to the Marriage Act 1961 (Cth) through the Attorney-General's Portfolio Miscellaneous Measures Act 2024 (Cth), to meet separately and in person with each party to a proposed marriage before solemnising it. The stated purpose is to maintain safeguards for "real consent." But the reform, while important, does not close the gap that estates lawyers and elder law practitioners have long identified between the capacity required to marry and the capacity required to make a Will, a gap that can have devastating consequences for families.

The 2024 Reform: What Changed

Before 12 June 2024, marriage celebrants were expected under their professional guidelines to satisfy themselves that each party to a proposed marriage was giving real, voluntary consent. Separate meetings with each party were recommended in cases where there were concerns about consent but they were not compulsory, and a celebrant could conduct the entire engagement process with both parties present throughout.

The Attorney-General's Portfolio Miscellaneous Measures Act 2024 changed this. The amendment to the Marriage Act 1961 introduced a mandatory requirement: every authorised celebrant whether a Commonwealth-registered civil celebrant, a minister of religion, or a State or Territory official authorised to perform marriages must now meet separately and in person with each party to the marriage before the ceremony takes place. The meeting must occur in the absence of the other party.

The purpose, as clarified by the Attorney-General's Department in guidance issued to celebrants in June 2024, is to ensure that each party has the opportunity to speak freely about their consent to the marriage, without the presence and potential influence of the other party. The reform is designed to address forced marriage and coercion, but it also specifically encompasses the question of capacity. Under the Marriage Act, a person's consent to a marriage is not "real consent" if that party did not have the mental capacity to understand the nature and effect of the marriage ceremony. A marriage solemnised where one party lacked that understanding may be void.

The separate meeting requirement gives celebrants a structured opportunity to form a view about each party's capacity and consent before proceeding. It is, in the words of the Attorney-General's Department, a safeguard not a guarantee. A celebrant who has concerns arising from the separate meeting must not proceed with the marriage until those concerns are resolved. A celebrant who proceeds despite having reason to believe there is a legal impediment to the marriage including an absence of real consent commits an offence under section 100 of the Marriage Act.

What Capacity to Marry Actually Requires

The capacity required to enter into a valid marriage is a matter of long-standing legal principle, established by decisions of Australian and English courts over more than a century.

The threshold is deliberately accessible. A person does not need to be of high intelligence or to understand all of the legal consequences of marriage. What is required, as the High Court of Australia addressed in Gibbons v Wright (1954) 91 CLR 423, is that the person must have the cognitive capacity to understand the general nature of the transaction they are participating in. For marriage, this means an understanding of what marriage is — a voluntary union between two people, to the exclusion of all others and an understanding of what the marriage ceremony is doing: creating that legal relationship.

This is a considerably lower bar than the capacity required to make a Will (testamentary capacity), which requires a person to understand the nature and effect of their Will, the extent of the property they are disposing of, the claims of those who might reasonably expect to benefit from their estate, and to be free from any disorder of the mind that would poison their affections or pervert their sense of right.

The asymmetry matters enormously in practice. A person in the early-to-middle stages of dementia may retain sufficient capacity to understand, at a general level, that they are getting married particularly in a ceremony environment where family members are present, the situation is familiar and structured, and they are receiving prompts and context cues. That same person may no longer have the testamentary capacity to understand the extent of their estate, the competing claims of their children, and the implications of the dispositions they are making.

In other words: a person may marry in circumstances where they could no longer make a Will. And when that marriage occurs, any Will they had previously made is automatically revoked.

The Revocation Mechanism: Section 12 of the Succession Act

Under section 12 of the Succession Act 2006 (NSW), marriage revokes a Will. This is not a discretionary outcome — it is automatic, immediate, and total. A Will executed the previous month, carefully drafted, properly witnessed, and reflecting decades of the testator's considered intentions, is extinguished by operation of law the moment the person marries.

There are limited exceptions. A Will that is expressly made in contemplation of a particular marriage either by identifying the intended spouse by name, or (in NSW) by being expressed as a Will made in contemplation of marriage generally is not revoked by the solemnisation of that marriage. A gift in a Will to the person the testator later married and the appointment of that person as executor also survive the marriage.

But these exceptions are narrow and require advance legal planning. A Will that does not include the necessary contemplation-of-marriage clause which is the vast majority of Wills in the community is revoked entirely by a subsequent marriage. Only the gift to the new spouse and their appointment as executor are saved, without any of the other dispositions, including gifts to children, grandchildren, siblings, charities, and others.

The position is stark: marry, and a Will prepared without the right clause is gone. For the testator who lacked capacity to make a new Will after the marriage, the result is intestacy.

Intestacy: Who Gets What

When a person dies in New South Wales without a valid Will including because their only Will was revoked by a subsequent marriage their estate is administered under the intestacy provisions of the Succession Act 2006 (NSW). The rules are statutory and admit of no discretion.

Where the deceased is survived by a spouse and children, the distribution under intestacy depends on the value of the estate. The surviving spouse receives all of the deceased's personal effects and a statutory legacy currently $623,405 (indexed periodically). If the estate exceeds that threshold, the surplus is divided equally between the spouse and the children. Where the estate is modest, the spouse may receive everything; where the estate is substantial, the children share in the balance, but the spouse's entitlement is substantial in all circumstances.

Where the deceased is survived by a spouse and no children, the spouse receives the entire estate.

These outcomes may differ dramatically from what the deceased person had actually intended for their estate. A person who had carefully planned to leave their estate to their adult children, or to specific charities, or to a testamentary trust for the benefit of grandchildren may find that their intentions count for nothing because their Will was revoked by a marriage that occurred when their capacity was already compromised, and they never had the opportunity to make a new one.

The Predatory Marriage Problem

The combination of a low capacity threshold for marriage, the automatic revocation of prior Wills upon marriage, and the substantial entitlements that flow to a surviving spouse under intestacy creates a legal pathway that can be and sometimes is deliberately exploited.

"Predatory marriage" is a term that has gained increasing currency in Australian elder law practice to describe the phenomenon of a person forming a relationship with a cognitively vulnerable individual with the specific intention of marrying them and thereby gaining access to their estate. The pattern typically involves a significant age gap between the parties, a relationship that begins in a position of trust (a carer, a neighbour, a social acquaintance), progressive isolation of the vulnerable person from their family, and a marriage that often occurs without the family's knowledge until after the event.

The legal effectiveness of a predatory marriage as a wealth transfer mechanism arises precisely from the gap between the capacity to marry and the capacity to make a Will. A person with moderate dementia may retain sufficient understanding of the marriage ceremony to satisfy a celebrant, while lacking entirely the capacity to understand that their marriage has revoked their existing Will, that they can no longer make a new one, and that their estate will pass to their new spouse rather than to their children.

The 2024 separate meeting requirement provides a genuine, if partial, protection. A well-conducted separate meeting, where a celebrant sensitively explores the party's understanding of the ceremony and their consent to it, may reveal concerns that would not be apparent with both parties present. But the reforms place the practical burden on celebrants who are, in many cases, lacking in specialist knowledge of cognitive impairment, have no access to medical records, and are meeting the parties for the first time. A predatory party who has managed the presentation of the vulnerable person throughout the relationship may have rehearsed the meeting.

What Families Can Do

The practical challenge for families who are concerned that a vulnerable relative is at risk of a predatory marriage or who have discovered that such a marriage has already taken place is significant. The law does not make intervention straightforward.

Before a marriage occurs, there are limited mechanisms available. NCAT's Guardianship Division may be able to make guardianship or financial management orders that provide some degree of oversight, but those orders do not automatically prevent a person from marrying. The Marriage Act does not empower a guardian or financial manager to prohibit a marriage on behalf of a protected person.

If a marriage has occurred and the family believes the person lacked the capacity to give real consent, they may apply to a court for a declaration that the marriage is void. This is a significant step, requiring medical evidence of the person's cognitive state at the time of the marriage ceremony. The process is expensive and emotionally taxing. And critically: even if a court declares the marriage void, the revocation of the prior Will may remain effective. A marriage that is void ab initio void from the beginning does not technically revoke a Will, but this is a contested area of law and families should not assume that voiding the marriage automatically reinstates the prior Will.

Where a person has died and the family is disputing the distribution of the estate, a family provision application under Chapter 3 of the Succession Act 2006 (NSW) may be available to eligible persons including adult children who have not received adequate provision from the estate. The court has broad discretion to make provision from the estate regardless of the intestacy rules, taking into account all relevant circumstances including the nature and quality of the deceased's relationship with the surviving spouse.

The Planning Imperative

The interaction between marriage, Will revocation, and intestacy is one of the least understood features of Australian succession law and one of the most consequential. For most people, the practical implication is simple: update your Will after you marry. But for families who have a cognitively vulnerable member, the implications are more urgent and more complex.

A Will that includes an express contemplation-of-marriage clause provides some protection, but only for future marriages that are genuinely intended. An Enduring Power of Attorney and Enduring Guardianship Appointment, put in place while the person has capacity, ensure that trusted people have legal authority to manage their affairs and personal welfare though, as noted, they cannot prevent a marriage.

The 2024 amendments to the Marriage Act represent a meaningful step towards protecting vulnerable people at the point of ceremony. But they address only the final stage of a pattern that, in the most serious cases, has been developing over months or years. The deeper protections lie in the estate planning arrangements made by individuals while they have full capacity and in the relationships that allow families to remain close enough to a vulnerable person to recognise when those arrangements are being undermined.

Shire Legal is a boutique law firm based in Miranda, NSW, specialising in property, business and estates law. This post is intended as general legal information only and does not constitute legal advice. You should seek advice specific to your circumstances before taking any action.