yes, most marriages fail. it's closer to 2/3 than 1/2.
the reason so many fail is because too many people are getting married that should know better. of the marriages that end in divorce, either they are precipitated by insolvency or unfaithfulness or they were doomed before they even began. out of the marriages that last for life, both people change but still stay together. some work their problems out, the rest are obviously bad marriages that do nobody any good - codependencies so strong that not even divorce can cure them.

im not trying to convince plugdrugs to rush out and get married
i'm trying to help him see that he wouldn't have a chance in hell of making any marriage or even a LTR work in the state he's in - particularly if he were to shoot for someone like lisa, as an example