What percentage of fast moving relationships usually end?

Someone very close to me has been with the same person for four years and decided that she does not love him anymore. She met someone else within a few weeks and fell madly in love with him. He says he is in love with her too. They are talking babies and moving in together. I can tell it's moving way too fast; why can't they?What percentage of fast moving relationships usually end?
I dont think there is a definite answer for this one. Every relationship is different. It all depends on how people get along and what they want . If 2 people are in a relationship-- and they BOTh want the relationship.. and take their time within the '; fast paced'; ( if that makes sense) to get to know each others likes and dislikes.. and what they want.. etc. then I see it working out. I went through a fast paced relationship-- that was over in 3 mths. I thought I knew this guy.. but I didn't. Its all a learning experience..What percentage of fast moving relationships usually end?
They are plain silly. This kind end up as soon as they start.
100%





SteveC