I am in the Strong camp. You opened the door. It had to start somewhere, but where it will lead no one knows. You do have to co-parent, but it does not in any way mean you ever have to accept her doing what she did without any remorse on her part.
Be patient with yourself most of all.
Me 45, H 46, S 23, M 26, Together 30, Bomb 6-2-08, S 6-19-08; H left 12-29-08. H home 12-09, Still MLC in 2012! Me- I have my big girl panties on. Bring it.