What is your W seeing when she watches you at home? Are you speaking at all? Doyou act mad or hurt? How do you act when the kids are around both of you?
Everyone makes mistakes in marriages. Your W is wayward and fully engulfed in her fantasy. Both of you have to be responsible for your own part. You can't take the blame for what she is choosing to do now.
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!
