This woman's opinion: a guy that knows stuff I don't know, who's interested and passionate about things that resonate with HIM, not just things that might impress ME ... THAT man is very attractive to me. You don't have to go overboard with the time spent, IMHO, because obviously that can be a problem too when you have committed to a family. But spend what time you do have wisely, and tap into some passion (I don't mean sexual, just life passion) that doesn't depend on your wife and kids.
"Show me a completely smooth operation and I'll show you someone who's covering mistakes. Real boats rock." -- Frank Herbert