A study in Portugal enlisted 1000 subjects who were asked to imagine themselves in a loveless, 10-year marriage. Would they stick or split? They were divided into four groups. The first group were just told they were in an unhappy marriage. The second were told they'd been married for only one year. The third were told that they'd bought a house together. The final group were told they'd put a lot of emotional effort into trying to save their marriage.
The results found that 35 per cent of people who'd put money or effort into the marriage would stay. They called this the "sunk cost effect": which is basically if we feel we are going to waste effort or money we put in, we will hang around.
