How do you get a STBX to admit her affair when she is in denial?
rich4j,
I doubt you'll get he to admit to the affair.
My approach, and it's probably not DB, is to go buy about ten big boxes and some packing tape. Go home, with boxes and tape in hand, and tell your wife she has to choose you or the OM. If she chooses you, then she'll have to be completely transparent; no more communications with the OM. If she chooses OM, then she has to move out immediately.
Don't do what I suggested without input from others. DB does not come naturally to me, but I do hate seeing nice guys being treated so poorly.