I believe SOME people do go through a mid-life crisis. My dad who was a teen when mom had me, married my mom and had a house by 19. He came from a wealthier family and was supposed to complete college. Work and family was demanding of him and it was difficult for him to get too far in it.
Oh dear...at about 36 or so something snapped in him! He went out and bought a fully loaded new car, had some cosmetic surgery, started tanning, working out, eating better...all these things were great! He was a bit flirty though with other females and of course this made Mom feel uncomfortable. He went and started some computer courses, got a second job teaching...this lasted I want to say, about a year, then, it was out of his system and I got my old dad back.
I wonder if people don't live life a little before rushing into marriage and family if they just bottle up regret until one day it explodes? There's more to the story of my dad, but I wouldn't want him to know I was sharing too much about him

.
My mom hit a period recently which is about a year since my brothers flew from the nest. My quiet and reserved mom is now volunteering and becoming social. I heard she was working out and I really hope this isn't a phase but she continues.
I don't think a mid-life crisis has to be a bad thing. Now, if my dad was going out with other women, that would be a different story. But he was commited to doing good for himself.