Answer:
exchange theory
Step-by-step explanation:
exchange theory explains the relationship between an exchange process and a particular social behaviour. It is a school of thought that believes certain behavioural pattern are influenced by exchange of benefits between individuals. This simply means a relationship/ interaction is established after individuals have estimated the cost and benefits of such relationship.
Exchange theory usually involves a cost and benefits analysis system to determine how much a relationship is worth. From this question, Peter uses the exchange theory to make a list of the costs and benefits of their relationship to decide whether to pull through the divorce or not