The only advantage of a much younger guy is the psychical part of a relationship.
Women in their 40s are more confident about themselves, and at their sexual peak. Guys have their sexual peak in their 20s / early 30s. So in that sense it's a perfect match. But only for that part ...

I still don't get why our creator pulled this trick on us women. I'd much rather share that with a man my own age ... But if you want seriously solid and/or 'ready to go for seconds' right away or within 15 mins ... you need a younger guy.
Other than that, I don't want a younger man. I need an emotionally and mentally mature man by my side as a life partner.