Is being in a relationship with your high school sweetheart through adulthood a success these days?

I often hear women on Y! answers brag about being with their hubbies since they were 17 or 16 and they're now in their 30s. Is this even possible? How do you stay with a person for that long and not get sick of them? I mean I'm in my mid-twenties and dated a guy in high school through my first 2 years of college. He turned into a different person, he ended up being a drunk and a womanizer, just like his older brother. He always fluttered my head with all these futuristic ideas of us being married. Lets be realistic here.......it never happened and it never will, but how is it possible for you folks to still be with your high school sweethearts?