I would think those with kids at that age that wanted them worked backwards from that mission, and if they have a midlife crisis it's some version of having spent too much time working and on their kid and start spending their money on low-impact possibly expensive hobbies they'd have liked to do in their younger years, somewhat in denial of the fact that they sold their whole life to the man despite raising a kid.
But that sounds nice! Let me reword: after getting through the messy middle of establishing a career and weathering the insane time and money necessary to rear a young kid, a dude finds himself with a little more time and money, and doesn't know what to do with himself. He gets a fishing rod/road bike/membership at makerspace/skein of nice yarn and some circular needles/signs up for his first powerlifting meet. He makes new friends, shows his kid a new side of himself, and maybe gets a nice steelhead/race trinket/dining table/scarf/medal out of the whole thing.