May I point out that more than half of of the times its a 20 yrs old girl who is getting attracted to a 40 yrs old guy. I dont know if they get attracted to a father figure or the fact that guy, his personality and his career are all set but I've seen it so many times that it is almost unfair to blame the 40 something guys for falling for a younger girl all the times.
Guys, in general are more attracted to a girl who makes sense as much as they are attracted to her physical beauty. I am sorry to say but most of our girls, almost to the age group of mid 20's dont even know how to talk properly. There world revolves around fashion and show biz. They are more interested in the love life of some cheesy bollywood hero than to listen to their own hubby and try to keep him happy.