Something is only wrong if the married person chooses to violate their spouses trust and commitment, so it’s still all on the married person, not The Other Woman.

The Other Woman has her own issues for sure, but the break up of a marriage is never the fault of the third party, it is the fault of the commitment breaker.

“Once a cheater, always a cheater” applies to the husband here. The Other Woman isn’t cheating, the husband is.