I like that analogy about the peg and the cow lol

I would say that if a lady, of normal libido, is satisfied by/with her man and they have a good and interesting ;o) sex life then she would have no need to stray - there would be no need unless, of course, there is something else wrong in the basic marriage or the woman is just plain, old fashioned, promiscuous!!!

Whatever, if one partner does go elsewhere for a bonk then the other is going to suffer a bruised ego for sure.