The Killers, "Mr Brightside"

Is it rational to stay in a relationship when you know your partner has been unfaithful? Standard economic theory assumes that we behave rationally: make logical and consistent choices that maximise utility. Behavioural economics use the concept of bounded rationality to explain why we make apparently irrational decisions. The principles of sunk costs and loss aversion offer an insight into why people remain in sub-optimal relationships.