...What i wanted to say is that things work well until she shows up and then things take a turn for the worse for S. (I did not mention that)....
Why did you want to say this? Think about it. Do you want to hurt her? Do you regret that there has been damage to their relationship?
Do you want to stand in the way or assist in bridging their reconciliation?
Do you think that what you would really like to say, has an underlying effect on how you interact with W?
I ask these questions in good conscious because I honestly think you need to consider your answers. I'm sure you have realized that I am not a "tell you all you want to hear" kind of person. This does you no good. I try to be the "tell you what you need to hear."
M 53 W 54, M since 98 D15, D19 8/2013 discovered EA, W maintained contact with OM until 10/14 7/2/17 W said she wanted S, 7/25/17 moved out of MBR 12/17 W says moving out 5/18, W still in home.