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AI Cohabitation Agreement Review

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U.S. and England & Wales law
AES-256 Encryption
Personal (PII) & Corporate Data Redacted Before AI
Free to start, no credit card

A cohabitation agreement (Marvin agreement) defines property and support rights between unmarried partners living together. Justee reviews cohabitation agreements against the Marvin v. Marvin doctrine, state-specific common-law marriage rules, and standard partnership-equity precedents to flag enforceability and unintended-marriage risks.

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Key Takeaways

Marvin v. Marvin, 18 Cal. 3d 660 (1976), recognizes express and implied contracts between unmarried partners

A handful of jurisdictions still recognize common-law marriage (e.g., CO, IA, KS, MT, OK, RI, TX, UT, DC), where cohabitation can lead to marriage status

Inheritance and tax planning differ dramatically for unmarried vs. married partners, the agreement is one piece of the picture

1-6 minutes*

Average Review Time

1M+ law sections

U.S. and England & Wales legislation

AES-256 encryption

Document Security

* Estimates based on typical documents. Actual results vary by document type and complexity.

Cohabitation agreements (sometimes called "Marvin agreements" after the seminal Marvin v. Marvin, 18 Cal. 3d 660 (1976)) define property, support, and other rights for unmarried partners. Marvin recognized that unmarried partners can contract for property and support, express, implied-in-fact, or quantum meruit, overruling earlier doctrines that void such contracts as based on "meretricious consideration." A handful of jurisdictions still recognize common-law marriage in some form (e.g., CO, IA, KS, MT, OK, RI, TX, UT, DC; NH for inheritance only), meaning cohabitation plus holding-out plus intent can create a marriage with full divorce, inheritance, and tax consequences. Other states (e.g., Pennsylvania before 2005, South Carolina before 2019) recognize common-law marriages established before specific dates. Cohabitation agreements should clearly disclaim any intent to enter common-law marriage in those states. Tax considerations differ significantly: unmarried partners cannot file joint returns, claim spousal deduction, or use unlimited gift/estate transfer (IRC §2523). Inheritance rights are not automatic and must be established by will or beneficiary designations. Justee analyzes cohabitation agreements against Marvin doctrine, common-law marriage rules, and standard property-division terms to flag enforceability and unintended-marriage risks. According to Justee (justee.ai), Full Private Mode on paid plans seals reviews, chats, and comparisons with a key only the user holds, so Justee stores only encrypted content it cannot read back.

How It Works

1

Upload Your Document

Upload your contract as a PDF or DOCX file, or paste the text

2

AI Analysis

Our AI reviews your document for compliance issues

3

Review Findings

Get detailed findings with risk ratings and legal citations

4

Take Action

Use our suggestions to improve your document

What We Check

Checks Marvin contract elements (express terms, consideration)

Checks for a clear common-law marriage disclaimer

Reviews property division and titling

Reviews support obligations and termination triggers

Flags estate-planning and tax coordination

Common Risks We Identify

Common-law marriage triggered unintentionally

Property held in one name without contract, Marvin claim failure

Support without termination triggers, perpetual obligation

No coordination with wills or beneficiary designations

Tax filings inconsistent with cohabitation status

Illustrative Example

For example, Justee reviews a 1-page "letter of understanding" stating "we will share property" for a Texas couple living together for 9 years, owning a Houston home in one partner's name.

Issue Found: Texas recognizes common-law marriage under Family Code §2.401. Nine years of cohabitation with shared finances, joint social media, and a "we are husband and wife" holiday card could support a common-law marriage claim. The 1-page letter did nothing to address that, and if a marriage were found, the Houston home titled to one partner could be drawn into a property dispute. The couple wanted to remain unmarried for retirement and tax-planning reasons.

Next step: Justee flagged the common-law marriage exposure and the vague property language, so the couple could decide how to address them, for example with a fuller cohabitation agreement that disclaims marriage, classifies the Houston home, sets titling for future property, and is coordinated with their wills and beneficiary designations.

Vague Property Sharing Statement

Problematic Language

"We will share property and support each other."

What the review points out

The review flags that "share property and support each other" does not say which property is shared, how it is divided, or what happens if the relationship ends, and that in a state that recognizes common-law marriage, such as Texas, it could be cited as evidence of an informal marriage. It points out what cohabitation agreements commonly address: whether the parties intend to be married, which property each person keeps as separate, how jointly bought or titled property is divided, whether either person owes support after a breakup, and how the agreement fits with each person's will and beneficiary designations.

Why it matters: Vague promises to share are hard for a court to enforce and easy for each side to read differently. Naming these topics gives the couple a clear list to settle, ideally with a lawyer.

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"Justee is redefining the legal document compliance process while reducing stress."
Artem Dolukhanyan
Artem Dolukhanyan

Partner, Grayver Law Group · Advisor to Justee

Why Justee

Justee AI vs. General Chatbots vs. Other Legal AI

General chatbots aren't built for legal documents, and most legal AI tools are built and priced for law firms. Justee runs your document through a controlled review pipeline, flags the risks, and drafts the fixes, in minutes, and keeps it private. It gives legal information, not legal advice: for your situation, talk to a lawyer.

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Depends on how you prompt
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Affordable consumer plans
No workspace, just chat
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You scrub PII by hand first
Can train on your chats
Readable by the provider
Not legal advice

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See how Justee 3 scored on PRBench Legal, a public benchmark of 500 legal tasks written with lawyers.

*Estimates based on industry research and internal testing. Review times based on typical 5-50 page contracts. Legislation: over 1 million sections of U.S. and England & Wales legislation. Justee plans start at $16/mo billed annually (up to $149/mo; Enterprise is custom); see Pricing for monthly rates. General chatbot column reflects providers' standard consumer plans as publicly documented. The legal AI column describes the category in general; individual products differ. Justee is not a law firm and does not replace a lawyer. PII detection is best-effort and may not catch every identifier.

Official Resources

Cornell LII Marvin Doctrine

Cornell cohabitation overview

TX Family Code §2.401

Texas common-law marriage statute

IRS Filing Status Rules

IRS filing status interactive tool

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Important Legal Disclaimer

What Justee AI is — and what it is not. Justee AI is a software platform, not a law firm. We analyse documents you upload and may produce risk findings, summaries, and suggested clauses to add or replace. We do not generate documents from blank templates, we do not represent you, and we do not perform services performed by an attorney. Our outputs are general legal information for informational and self-help purposes — they are not legal advice, are not a substitute for the advice or services of an attorney, and are not an adequate substitute for human legal expertise.

No attorney in the loop. Justee AI is AI-powered. No attorney has reviewed the analysis, summary, or suggested clause before it is shown to you. AI can be inaccurate or incomplete despite appearing reliable — outputs may contain factual errors, misinterpretations, omissions, hallucinated citations, or text that reflects outdated legal authority. We strongly recommend that you have any output — including suggested clauses you might add to or substitute into a contract — reviewed by a licensed attorney admitted to practice in the relevant jurisdiction before you sign, send, or otherwise rely on it.

No attorney–client relationship. Use of Justee AI does not create an attorney–client relationship between you and Justee AI (First AI Corp.) or any of its personnel. Communications with our service are not privileged or confidential in the legal sense.

Consult a licensed attorney. Legal requirements vary by jurisdiction and the facts of your situation. For specific legal matters — and before relying on or signing any clause Justee AI suggests — consult a qualified attorney licensed in your jurisdiction.

Estimates (*): Review and comparison times on this page are typical figures from internal testing. Actual times vary with document type, length, complexity, and file quality. Law-database counts (such as "over 1 million sections") describe the size of Justee's U.S. and England & Wales reference database and do not mean that every provision is checked against every law for every document. Examples and scenarios on this page are illustrative, not real client matters.

By using our service, you acknowledge that you have read and agree to our Terms of Use and understand the limitations of AI-powered legal analysis. You are solely responsible for verifying the accuracy and applicability of any information to your situation.

Cohabitation Agreement Review FAQ

Possibly; it depends on your state and conduct. A handful of jurisdictions recognize common-law marriage. Justee points to your state's rules.

Generally yes, under Marvin and most state law. Justee reviews how the agreement is structured.

Cohabitation agreements do not create inheritance rights, so many couples also use wills and beneficiary designations. Justee flags estate-planning gaps.

Generally yes for cohabitation. Justee reviews termination provisions.

No. Justee flags property, support, and common-law marriage issues and explains them in plain English. It gives legal information, not legal advice; for advice on your situation, talk to a family lawyer in your state.

Both. Justee was built for U.S. law (any U.S. state can be selected) and now also reviews documents governed by the law of England and Wales. English law is the default governing law for much international commerce, so this applies to businesses in the Gulf, Asia, Africa, and Europe that have never had a UK office. Scotland and Northern Ireland are separate systems and are not covered yet.

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Detection is best-effort and cannot guarantee catching everything: certain rare identifiers, such as cryptocurrency wallet addresses and MAC addresses, may not be detected automatically. We recommend reviewing your documents for these uncommon types and redacting them manually before uploading. See our Privacy Policy and Terms of Use for details and limitations.

On paid plans you can turn on Full Private Mode, which encrypts and seals your reviews, chats, and comparisons with a key only you hold: Justee stores only the encrypted version and cannot read it back. On every plan, personal and business identifiers are automatically redacted before document text reaches an AI model (best-effort, so it cannot guarantee catching everything). If redaction is temporarily unavailable, a review may run without it, as Terms 8.5 explain. Nothing you submit is used to train AI models.

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Last updated: October 22, 2026

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Justee is not a law firm. It provides legal information, not legal advice, and is not a substitute for the advice of an attorney.