This article describes research in developing a new theory of decision support in negotiation in family law mediation. AssetDivider was based on the principles of Family_Winner. As a Negotiation Decision Support System Family_Winner take ratings assigned to items by the parties involved and develops a list of allocations to each party; based on trade-offs inherently present in the dispute. Given advice provided from our industry partners Relationships Australia (Queensland) – RAQ, AssetDivider uses an ideal “percentage split” to guide the development of an allocation list for parties. The system has been tested informally by our contacts at RAQ, and we now look forward to extensive testing and evaluation by mediators at RAQ in the near future. We expect observations and comments made by mediators evaluating the system to indicate future developments, in particular in developing new research into emotionally intelligent NDSS.