In my experience, "once a cheater, always a cheater." It works both ways. KK will always be inclined to cheat, even though she has license/consent from me to enjoy sex with other men - I fully support both aspects. Cheating, defined as clandestine or otherwise undisclosed sex with others is part of KK's personality, and the way she manifests certain needs and desires.
I could spend the rest of my life failing to accept that, objecting to it, without ever being able to change the behavior. I've learned to accept and enjoy it.
The other side of it is my own needs. KK is insanely, homicidally jealous when it comes to me and other women. Like KK, I've engaged in affairs, from one-night stands to complex, more traditional affairs, fathered children with affair partners, etc. I don't plan to stop, although I conduct these infidelities in a much different manner now.
Monogamy is a strange societal construct - in my opinion it runs counter to nature.