Cohabitation Agreements + Unmarried Couples in Idaho… | CGMIMM
Family Law · ID
Cohabitation Agreements + Unmarried Couples in Idaho
Idaho unmarried couples have NO automatic rights to property, support, or inheritance — cohabitation agreements + careful estate planning are the only protection. "Common-law marriage" is rare + specific.
Published May 9, 2026
## Cohabitation agreements + unmarried couples in Idaho
**Unmarried couples** living together have FAR FEWER rights than married couples. Idaho unmarried partners have no automatic rights to property division, alimony, or inheritance — but a properly drafted cohabitation agreement provides similar protections.
## Default rights — limited
**WITHOUT cohabitation agreement / will, unmarried partners:**
**No marital property:**
- Property follows title
- Joint titles share equally
- Individual titles stay individual
- No equitable division
**No spousal support:**
- No alimony obligation
- No support after breakup
- Each party self-supporting
**No inheritance:**
- Without will, partner gets nothing
- State intestate laws favor blood relatives
- Need will / trust for partner inheritance
**No medical decisions:**
- Without healthcare directive
- Family of origin makes decisions
- Often legal disputes
**No emergency contact:**
- May not be allowed in hospital
- Family of origin notified
- Specific HIPAA issues
**Limited social security / pension:**
- No spousal benefits
- Survivor benefits often denied
- Specific to programs
**Limited estate tax benefits:**
- No marital deduction
- No portability of exemption
- Estate tax issues
## Common-law marriage exceptions
**Limited recognition:**
**States that still recognize:**
- Colorado
- Iowa
- Kansas
- Montana
- New Hampshire (limited)
- Oklahoma
- Rhode Island
- South Carolina
- Texas
- Utah
- DC
**Other states recognize if validly created in another state.**
**Requirements (vary by state):**
- Capacity to marry
- Present agreement to be married
- Cohabitation
- Holding out as married
- Specific time period (some)
**Not just living together** — requires intent + holding out.
## Cohabitation agreements
**Like prenup but for unmarried:**
**Purpose:**
- Property rights during relationship
- Property division at separation
- Financial support obligations
- Specific responsibilities
- Dispute resolution
**Generally enforceable when:**
- In writing
- Voluntarily signed
- Full disclosure of finances
- Specific to property + financial issues
- NOT for sex / morality / illegal purposes
**Marvin v. Marvin (CA 1976):**
- Established palimony / Marvin claims
- Implied contract from relationship
- Specific to express + implied agreements
- Limited to specific facts
- Many states reject
## What cohabitation agreement should cover
**Property:**
- Pre-relationship property
- Property acquired during relationship
- Joint vs separate ownership
- Specific property division
- Inheritance treatment
**Finances:**
- Income contribution
- Expense sharing
- Bank account arrangements
- Debt allocation
- Specific obligations
**Support:**
- Whether support obligations exist
- Specific terms
- Duration
- Modifications
**Children:**
- Specific child considerations
- Cannot bind future child support
- Specific custody (limited)
**Termination:**
- What happens at separation
- Notice procedures
- Specific process
- Property division
**Dispute resolution:**
- Mediation requirements
- Arbitration
- Specific procedures
## What cohabitation agreement CANNOT cover
**Generally:**
- Sexual conduct as consideration (illegal)
- Future child custody (limited)
- Future child support (binding)
- Specific illegal purposes
- Unconscionable provisions
## Same-sex couples + Obergefell
**Major shift (2015):**
- Same-sex marriage legal nationwide
- Marriage provides protections cohabitation doesn't
- Strong recommendation: marry if possible
- Estate / immigration / tax benefits
- Specific advantages
**For unmarried same-sex couples:**
- Same considerations as opposite-sex
- Cohabitation agreement valuable
- Estate planning critical
- Healthcare directives
**Currently litigated:**
- Obergefell sometimes challenged
- Specific to political environment
- Some marriage protection legislation
- Always check current law
## Necessary documents
**Cohabitation agreement** alone insufficient. Also need:
**Wills:**
- Each partner's will
- Specific bequests
- Otherwise intestate distribution to family
**Healthcare directives:**
- Living will
- Healthcare power of attorney
- HIPAA authorization
- Designated decision-maker
**Financial power of attorney:**
- Specific authority
- During incapacity
- Financial decisions
**Beneficiary designations:**
- Retirement accounts
- Life insurance
- Specific accounts
- Update for partner
**Joint property structures:**
- Real estate (joint tenancy / TIC)
- Bank accounts
- Investment accounts
- Specific titling
**Trust documents:**
- Living trust
- Specific provisions
- Avoid probate
- Privacy
## Specific scenarios
**Joint home purchase:**
- Title together (joint tenancy or TIC)
- Specific ownership percentages
- Down payment treatment
- Mortgage responsibility
- Buyout provisions
- Sale provisions
**Joint business:**
- LLC / corporation structure
- Operating agreement
- Buy-sell provisions
- Specific business terms
**Children together (unmarried):**
- Parentage establishment
- Custody + support
- Specific procedures
- ${s.name} requirements
**Children from prior relationships:**
- Specific inheritance considerations
- Stepparent issues
- Specific estate planning
## Breaking up — process
**Without agreement:**
- Each takes own property
- Joint property must be divided
- May require lawsuit ("partition")
- Specific procedures
- Often messy + expensive
**With agreement:**
- Follow agreement provisions
- Specific procedures
- Mediation often
- Specific remedies
**Joint property issues:**
- Real estate sale
- Bank account closure
- Joint debts
- Specific procedures
## Tax considerations
**Different from married couples:**
**Income tax:**
- File as single
- No joint return
- Specific tax brackets
- Different deductions
**Gift tax:**
- Transfers may be gifts
- $19,000 annual exclusion (2025)
- Lifetime exemption
- Specific reporting
**Estate tax:**
- No marital deduction
- Limited spousal benefits
- Specific planning needed
- Significant difference from married
**Property tax:**
- Some states homestead protections lost
- Specific to ${s.name}
- Property reassessment issues
## Insurance considerations
**Health insurance:**
- Many employers cover domestic partners
- Specific to employer
- Tax implications (imputed income)
**Life insurance:**
- Beneficiary designation needed
- Specific to policy
- Insurable interest issues (limited)
**Auto insurance:**
- Joint policies sometimes
- Different rules
- Specific coverage
**Renters / homeowners:**
- Joint policies
- Specific coverage
- Specific liability
## Domestic partnerships + civil unions
**Some states still offer:**
**California:**
- Domestic partnerships
- Most marriage rights at state level
- Specific requirements
**Other states:**
- Specific procedures
- Limited rights typically
- Specific to state
**Federal recognition:**
- Limited
- Tax issues
- Federal benefits
- Specific differences from marriage
## Practical tips
**Before moving in:**
- Discuss financial expectations
- Discuss long-term plans
- Discuss children plans
- Document agreements
- Consult attorney
**During relationship:**
- Maintain financial records
- Keep some separate accounts
- Document significant gifts / transfers
- Update documents regularly
- Specific milestones (purchases, kids)
**Major decisions:**
- Real estate purchase
- Major financial commitment
- Children
- Specific tax implications
- Specific legal review
## Costs
**Cohabitation agreement preparation:**
- $1,500-$5,000+ typical
- Comprehensive package
- Includes related documents
- Worth the investment
**Comparison to litigation:**
- Without agreement = potential $25K-$200K+ litigation
- Significant savings
- Specific to circumstances
## Common mistakes
- **No agreement at all** (most common)
- **Verbal agreements** (unenforceable)
- **Outdated documents** (life changes)
- **No estate planning**
- **No healthcare directive**
- **Joint accounts without agreement**
- **Real estate without specific titling**
- **Children without parentage establishment**
- **Specific tax problems**
## What you should do
If you're in a cohabiting relationship in Idaho: hire a family-law attorney for cohabitation agreement + estate-planning attorney for wills + healthcare directives. Many Idaho family attorneys handle these matters. Cost typically $2,000-$5,000 for comprehensive package. Consider marriage if possible — provides far stronger protections. Update regularly.
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*This guide is general information about Idaho law as of mid-2026 and is not legal advice. Cohabitation issues are technical. Talk to a licensed Idaho family-law + estate-planning attorney about your specific situation.*
This guide is for general information only and does not constitute legal advice. Laws change and outcomes depend on your specific situation — talk to a licensed attorney before acting on anything you read here.