Domestic Contracts - Separation Agreements, Cohabitation Agreements and Marriage Contracts The vast majority of couples resolve their differences on relationship breakdown by negotiating then signing a separation agreement. This is an agreement in writing that deals with issues such as the division of assets, custody and access, support etc. It is a contract between the parties. We are seeing more and more cohabitation agreements and marriage contracts also. If clients have been through a separation then they often recognize the potential benefits of such agreements.