Hang in there dawgy. You know as well as anyone that there is really nothing you can do about your Ws actions. She is on her own journey. Believe me I know it stinks and it hurts more than anything. Just do your best to not focus on her, and work on that detachment. I am having to do the same right now. I had been a model detacher and the past few days have been kinda rough.
Keep yourself busy and occupied to help keep your mind off of it. Your feelings of panic will lessen with time.
If your W is saying she wants to live with the OM, then there is nothing you can do to stop her. If you have been ok with OM up until now, why does this change anything? If nothing else, she will start to see the non glamourous sides of him.
Me: 42 W: 32 Married 7 years together 8.5 S1: 7 S2:7 Bomb #1: 09-16-13 Recon #1: 11/13 A discovered 04-03-2014 W filed D 05-19-14 but never served me I filed D 12-02-2014 S 05-31-14 Divorced 5-19-16