I understand where y'all are coming from. My original Diamond graduated my freshman year. We stayed in touch, but superficially. We actually worked across the street from each other for 2 years and never even had lunch!
My second Diamond was depledged for Standards reasons, and ended up a member of another sorority!

I often wondered if they had a different set of Standards than we, or did she just hide things better!
My last Diamond was my very best friend. We had a falling out when I got married, and while we're still friends, it's not the same. We see each other at a reunion every year, but that's about it.
But the best part of being an Alpha Delta Pi is that you're not just close to the sisters of your chapter - you have an entire country full of sisters! Some of my closest friends now are sisters from other chapters, and while the core of sisters with whom I was close in school have scattered around the world, we are still in touch on a regular basis.
One of the best sayings I've ever heard was "You Gotta Wanna". If you want to do something badly enough, you will. If you want to stay friends, you probably will make the time to keep in touch. Any time I start feeling pouty about missing someone (or not losing some weight, or making enough money, or, or, or), I realize that I obviously just don't want it enough. It works for me!!!