A new study from the Max Planck Institute has found that married Europeans are showing a divorce spike after five years, rather than the old seven-year itch. They interpret this as showing that people today get bored with one another faster.
I disagree. The seven-year itch always made sense on sociobiological principles. Seven years after the wedding, many couples will have two kids, and the youngest one is likely to survive childhood. If he is going to leave, or if she has had enough of him, each can imagine that a divorce at that point would not imperil the children's survival. The adults might imagine that they are young enough to remarry, even have more children, if they leave then. They might even think that it would be better for the kids if they didn't remember life with the absent parent.
Most couples today cohabit for a year or two before marriage. They might even have kids in that state. In fact, it is often the pregnancy that pushes the cohabiters to marry in the first place. When we add in cohabiting years, the new five-year itch is pretty much the same as the old seven-year itch. All that has changed is where in the seven years the wedding occurs.