Your wife doesn't like the idea of being honest about cheating on you because her social standing is more important to her than indulging your desires. Females cheat just as much as males, and they have vastly more opportunities to do so, however the last thing any female wants is for anyone to ever figure out that she is a slut, so they lie about how many men they have been with, claim they are virgins, and all the rest to conceal from everyone publicly what they are really doing in private.
I can assure that is some "bad boy stud" came along your wifes panties would drop without hesitation because that is how she is wired no matter what she says to you, and after that random jackass fucked her in an alley she would come home and bake cookies like Suzie homemaker and never mention it to you because her social standing as a innocent Christian girl is far more important to her than anything else.