To take joy in returning to the pleasures and ways of the past is not necessarily nostalgia. Sometimes one will be clinging sentimentally to the idea of some golden age, and as a way of not letting go of one's youth, which is what I think of as being nostalgia in the true sense. But other times, enjoying the company of good people really is just a great experience worth trying to preserve. It was excellent in the past when you got to do it all the time, and it is still excellent when you get to do it now, albeit less frequently. Unlike getting old, I can proudly say that I did reflect at the time on what a rare pleasure it was to spend one's time with excellent companions.
Congratulations on getting married, old friend.