This isn't always the case Allen. You state it as though it is fact but it is your opinion, and it is not correct always.
And usually an OW is a sympton........whatever Puppy states. A symptom you want rid of, but all the same a symptom.
Saffie,
You mean, sorta like you just did right there?
The presence of another person in a marriage via an affair isn't just a "symptom," unless you want to say that gasoline is a "symptom" of a conflagration. It is an obstacle and an IMMEDIATE THREAT to the family and to the very marriage itself.
"Nagging" is a marital "symptom." One spouse not doing their fair share of the housework, leading to resentment -- that's a "symptom." Communications issues -- symptom.
An OM/OW who is preying on your marriage is . . . well, they are a PREDATOR, and should be dealt with as such.
