No, she is too ashamed to tell her family. She had spoken to them about the friendship she had with this OM and they had warned her of the danger she was getting into. It seems I was the last to know about him.
You need to call them all today, tell them about the affair without forewarning her and enlisting their help. Affairs thrive on secrecy, so keeping this a secret will ony serve to enable it. Exposure will likely stop this affair dead in its tracks. Call her family and then call and tell your children. The more people who know, the more people to hold her accountable.
Don't skip this step, DC!
The issue of exposure comes up when a betrayed spouse has first learned about the affair. Should it be exposed to others, or kept secret? I generally recommend exposure. When should it be exposed? I usually recommend that it be exposed immediately. To whom should it be exposed? I recommend that family, friends, children, clergy, and especially, the lover�s spouse be informed. Exposure in the workplace depends on several factors.
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Exposure is very likely to end the affair, lifting the fog that has overcome the unfaithful spouse, helping him or her become truly repentant and willing to put energy and effort into a full marital recovery. In my experience with thousands of couples who struggle with the fallout of infidelity, exposure has been the single most important first step toward recovery. It not only helps end the affair, but it also provides support to the betrayed spouse, giving him or her stamina to hold out for ultimate recovery.