People are by nature polygamous. If you have monogamy, then the flag is in your hand. And when a couple’s relationship is built on the unification of souls, not a whisper, then there may be an option that they both like to have fun together in sex clubs, swing and all that. If both spouses agree on this option, then the concept of betrayal is clearly drawn by your ears here.

You forgot to add the word "some". Some people are polygamous and do not object to the polygamy of the partner. They are lucky. Worse, if such a polygamous coincides with a monogamous. It is very bad when the polygamy itself, and from the partner you expect strict monogamy (black men almost always require absolute loyalty from wives and mistresses, up to the sweater in the floor and the eye down).