I've coined the phrase "Salmon Years" for this point in life. Spawned, now rolling down stream waiting for the bear.
I wouldn't say I'm in a 'mid-life' crisis but I have ramped up activities I fear not being able to do well in 10 or so years.
Music for one...I'm in two bands, recording, gigging, having a blast. Took up kayaking a couple of years ago too. Playing music in regular Irish music pub sessions as well.
You know your doing it right when the wife and grown kids start noticing you are 'busy' doing your own thing, more often. I've supported them, now I support ME!
(fun to say....I'm still very responsible for "them")