This study aims to get an empirical model of customer behavior in deciding to buy life insurance that is combined with financial investment. The underlined concept of this research is the marketing theory of relationship based on social interaction and resources (RbV), social exchange theory and agency theory. The object of this study was conducted on private life insurance companies in Semarang with as many as 140 respondents. The technique used is purposive sampling with criteria of life insurance customer. Satisfied customers will behave and talk positively about the company, make continuous purchases and volunteer bring friends, relatives and people around them to buy products. Co-synergy is a synergy collaboration between insurance agents and customers to produce co-creation value. Sales persons (insurance agent) as a moderating variable because of the role of insurance agents as value creators who represent the company. Insurance agents who play a very important role in presenting the information on the rights and obligations of customer's transparently also serve as customer's financial consultants. It is proved that insurance agents are not able to moderate collaboration on the value of insurance.