Infidelity may have less impact in Europe simply because that behavior was modeled for centuries by the aristocracy.

Even if there were no sexually transmitted diseases, the betrayal of a marital vow that is either expressed or implied is unquestionably wrong. There is no justification for this kind of self-indulgent behavior.

This isn't the same as going from winery to winery in Napa Valley and sampling cabernets.

A marriage without fidelity is not a marriage; it is a limited partnership.