Not a critique to anyone, just thinking about the question...
Well, wife's pussy belongs to me (husband), and one of main reasons is the fact that with me she can also have other men cocks as well - and frequently. And the game pleases us.
Fact is, she wouldn't be able to taste such LS with...
Because...
The jealousy and excitment mixture is very arousal
She gets more creative, willing and vivid for anything related to sex
She needs it
And the main reason...She is a slut!