I've talked about this over drinks with the wife/friends. The problem with dating someone WAY younger is they don't relate with your experiences- they grew up in a completely different time period. Successful relationships are based on commonality- hence the name "RELATION-ship". Men are wired to visual attraction, so young healthy bodies are a big draw for us...but that's just physical attraction. If two people don't have anything more than that, it will never work.
I'm 49 now, and when I look at women in their 20's, I see my daughter's friends--and when I hear them speak my brain immediately goes into "dad mode." I don't think I could date anyone more than 10 years younger than me (not that I would ever do that...my wife is hot

)