Relationship fail means that two people aren't meant to be together and don't want to work as a team like a married couples should. Relationship is a commitment between each and every couples of having to work on making decision between each other. Also you don't work as a team nothing is doing work in your relationship and it will fail. Many relationships are caused by financial problems, cheating, abuse, and so on. For example, I know with me being also married for three years in a relationship that you have to work & try harder every time that you think you can do better than the day before.
Today, many relationships don't last long because of some problem that causes them to break up. But the question is "Why do you want to get married or be in a relationship in the first place?" The reason why is because they want sex. Most couples or relationships happen quickly because the girl gets pregnant because they have sex before married or messing around with person out there than they wonder why there life is so messed up.