Brother, I am in the same sitch. My W started seeing OW as a friend. I was traveling and she kept "being there." W finally slept with her at least three times, once I caught them. W moved out last month. got the ole I love ya but,,, speech.
Now she is in the throes of a MLC and the OW is still there "as a friend." too needy and clingy also. OW has a reputation for screwing with married women and triggering MLC.
Only one to blame is W. Currently working on myself only. That is what this site is all about. A place to vent and find yourself. Find help and understanding while we wait out our spouses return to reality.