Late spring is upon us, and with it comes wedding season, the time of year that inspires a peculiar mix of sentimental stories about chance meetings leading to love alongside gloomy commentaries about the chances of marital happiness. Both the sentiment and the gloom are based on misguided ideas about the history and evolution of marriage — myths that, from this day forward, we should divorce from our notion of wedded bliss.

1. People don't value marriage the way they used to.

Modern Americans do put less emphasis on marriage as an institution that should organize everyone's life, but they put much more value on it as a relationship based on fairness, intimacy and fidelity. That is, paradoxically, one reason they have become more tolerant of divorce. For example, a May 2010 Gallup poll found that while only 23 percent of Americans believe divorce to be morally wrong, 92 percent believe it is immoral for a married man or woman to have an affair — the highest disapproval of any topic in the survey.