nah, my parents broke up three times before they got married. Different reasons, a lot of it being because my dad wasn't mature enough, and didn't appreciate my mom. One time they didn't talk for 5 months, then saw each other in the library, and he asked her back out.
Now they've been happily married for a good amount of time now. I hear a lot of stories like that. Now, there are a lot of relationships that don't work the second time around, but like Panda mentioned, thats only if the intentions and reasons are all wrong.
With your friend, she probably never really lost the feelings for her ex, and thats why she could so easily jump back into a relationship with him. I'm sorry you're suffering through this, but basically you just need to wait it out and figure out what THEIR scenario is, because every relationship and every couple is different
Cinderella said to Snow White
"How does love get so off course
All I wanted was a white knight
With a good heart, soft touch, fast horse
Ride me off into the sunset
[URL=http://dizzygirl.net]Baby I'm forever yours[/URL]"