Although it may seem unnecessary to have a cohabitation agreement just for living together, it does provide some benefits and protections. Breaking up, especially if you live together, can be complicated and expensive. Without a contract, you could be on the hook for some of the debts of your partner, or you may have to divide some of your separate possessions with your now former partner. If you and your partner purchased any real estate or assets together, it could be messy if you do not determine ahead of time how to divide them.