Mmm...interesting thread,
I hadn't really thought about it but I walk through my town on a Sunday morning to go and do my hobby. I notice a group of 40 year old blokes stood in a group with bikes. Only ever one woman or maybe two and no young men.
I am a man and started my hobby in my 40s. I think that men have to make peace with themselves in their 40s. Declining health, declining/stalled career, declining manhood. You make peace with yourself by accepting what you are, looking at life with wisdom and deciding to enjoy life, enjoy your partner, enjoy your children. That's why men take up cycling, restoring classic cars, taking on an allotment, or spending more time in their shed. Its part of sitting back and taking the foot off the 'breadwinner' accelerator pedal.
The problem is that sometimes their life partner is a woman who put her life on hold with children and she wants to get out there and make the most of what is left. She doesn't necessarily want to be with man who wants to sit back a little and spend more time with his bike, car, allotment or shed.
I think women have a MLC at the same time as men. In their early 40s women first of all have to accept they will not have a(nother) child, accepting they wont perhaps get back to that career they once had. I know my wife struggled with that. We have a strong relationship and I would like to find a new challenge for both of us to enjoy together.