I dont think marriage has really changed over the years. Yes many more people get divorced these days. I dont think that is because people are making bad choices or love dosn't work these days (maybe they have a very small effect).

I think it is because there is no social stigma behind getting divorced anymore. 50 years ago people would just keep the marriage going and live unhappily. So now the only thing that has changed is that people can leave unfulfilling relationships