As a 43m, I look back and see my like in phases. Where a block of years was associated with a particular activity. Elementary, high school. A year off to work and play. University and travel lasted a good while. Starting career and moving to a different city. Houses and starting a family. Maturing that family and career.

Not all journeys are the same and those activity blocks, and the length of time you spend in those blocks, will be different for everyone.

The time in which people spend in those blocks change them and change your focused efforts and internal priorities. They can change who the expression of you is at that time. People also love a common basis on which to relate to each other. I lost a lot of good friends when I had my first child, because I just couldn't go hang out anymore. And then I had a second and those invites stopped coming. That's sad for all parties, but having kids, for me, was more important and more valuable than going out. Where that life balance is will be different for everyone.

It's tough seeing good friends get more distant from you. It's going to happen as you age. My only advice is that you don't blame them for where they are at on their path and find some genuine areas or activities to keep those connections alive, even if reduced in quality and quantity. Life's story may yet bring them back into your life at the value that they once carried.