Marriage comes with a legal framework for property, debt, and support built in by default. Unmarried couples don't get that framework automatically — a cohabitation agreement is how they create it themselves.
Who owns what
Without an agreement, ownership of shared property can come down to whose name is on the title or who can prove they paid for what — messy territory if the relationship ends. A cohabitation agreement spells out ownership upfront.
Shared expenses and contributions
Rent, mortgage payments, and household expenses often get split informally while a couple is together. Documenting how contributions are tracked protects both people if there's ever a dispute about what each person put in.
What happens if you separate
The agreement can set out how jointly owned property, shared accounts, and even pets are divided if the relationship ends — decided in advance, rather than negotiated during a breakup.
It's not just for long-term partners
Couples moving in together for practical reasons — splitting rent, buying a home together before marriage — benefit from the same clarity as couples who've been together for years. The agreement matches the situation, not the relationship's length.