Why dont most Relationships last?

Is it our generation? Have we become too fast and self centred that we have lost the patience? I see people around me, dating for a while then either cheating on their partner or breaking up for minor inconveniences as if it never mattered. Infact there was one couple in our college who I was sure of will end up togehter, man they were dating for 4 to 5 years now. But as soon as they passed out I am hearing rumors that they broke up. Was it similar with the previous generation? Or has our generation become too blindsighted by the fancy concepts of hookup culture/situationship/casual relationship? What are your opinions?