Your W is bouncing from man to man. She needs counseling for herself before she's ready to stay M. She's a serial cheater, and the M won't stand a chance unless she realizes she needs help and then sees the therapist on regular sessions. After she makes some progress, the maybe the two of you could get MC.....if she's willing to stay in the M.
Do you think your W is on drugs? I would be very concerned over her leaving her little 3 yr old unattended while she partied. Has anything like that ever happened before or since?
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!
