, I so want to agree with you, but I'm afraid that I don't. Or, at least not exactly.
cjadek's wife should bear the full weight of the damage that she did to her marriage in pursuing a secretive, inappropriate, self-serving relationship with another man for 15 years. The OM should bear the full weight of his betrayal of his marriage vows. They each need to assume complete culpability for their own spouse's pain.
I think cjadek's wife should be focused on cjadek and not on dealing with guilt for trangressing the bounds of common decency. Yes, her actions and choices impacted the OM's wife. Yes, she did not behave in a decent or honourable way. But frankly, that behaviour was incidental not deliberate. And the guilt that she should feel around this is way down on the priority list. She did not break any promises made to the OM's wife or even have any bond with her * (not sure whether she had even met her?). Trying to hold the OM or OW accountable in some way for the BS's hurt allows blame shifting from the WS. It's also a cunning tactic we BS's often try to use on our own to make our WS's more palatable - it wasn't their fault, they were tempted, misled etc. IMO, we need to honestly and objectively confront the offending part of our WS if we are to have any chance of forgiving them or even considering an effective reconciliation.
From my perspective - as a BS, it is entirely OK to loathe the OM or OW. (There are recently elected presidents that I loathe with far less personal reason.) I have very little respect for my husband's OW. But she really shouldn't matter to me at all. And to say that she "should have been a better person and considered my feelings"? Frankly, it feels a little toothless.
So to say that cjadek's wife should be weeping for the "pain she caused" the OM's wife. I'm not sure that it is useful... or realistic. We should all be striving to be better people and challenging ourselves when we fall short of that. I hope that one day, cjadek's wife does think about the pain caused this other woman so far away by her actions and inaction. And that it makes her a better person. But for now, all her energy should be on her marriage and on cjadek.
(* Where the OW or OM is a person that the BS has a relationship with (beyond acquaintanceship), then I have more complex feelings. But, even in this case, the additional pain the BS is feeling comes from the betrayal of their own relationship with the OW or OM. And that should be processed separately.)