Studies have shown that men do gawk, but we don't need studies to know it's true!
It almost seems to be part of their genetic code, while women are more wired for a wider range of attributes in men to determine how likely they are to be good and faithful providers during the dependent years of child rearing.
Many people claim that husbands who gawk are more reliable and less likely to stray than men who don't.
Ask him to tone it down, but also try to think of some witty ways to deal with it, such as 'Honey I need $300 for the same outfit and hairdo she has.' If he says 'it wouldn't do any good' say 'that's right, she spent at least twice that.' Use your wiles.
You can even pretend to notice some handsome guy on the other side of the room, and gawk and say WOW now there's a good looking guy. A little tit for tat, a dose of his own medicine, and a lesson - without any harm done.