Don't speculate or you will drive yourself crazy and it will take your focus off what needs to be done.
The only facts you have right now are (A) he is visiting this weekend and staying the the marital home (B) your W has plans to go bowling with OM and the children and (C) the cell/text records. Anything further speculation is a waste of your mental energy and time. YOU MUST DETACH.
I don't care if you have to physically sew your lips shut. Do not say a WORD to your W about ANYTHING. Do not send her *any* texts or e-mails - tie your hands if you must. Consider any contact you have with her as ammunition to be used against you.
I know this is going to be hard to hear but there were not any glimmers of hope in a very, very long time. You wanted to see glimmers so you accepted any crumb. I am glad you decided not to allow your W to lead you around on a leash anymore. It's no way to live and solidify an amazing future for you and your girls. And you certainly don't want your girls to follow in your W's footsteps. Be the better example by being civil, respectful and strong. It is an absolute thing of beauty to see you finally getting on this path.
