One point, you keep going over and over if she has had an affair. I did and still do. She did, is, whatever....My W never admitted to anything and really struggled to admit to that which I could undeniably prove - some of that she still denies. When you have let go (detached etc), you will stop doing this. I think the best indication of this is when you are kind of 'yes, it's sad, but hey, I'm not I am happy and so are the kids'. I am 99% of the time at a place where I am very happy and just think she is a fool to have given up on us. I do feel sad for her (the kids mostly - they are totally happy though), but hey.
The lady company thing. You need to be in a better place first and ideally on the other side of a D. If filing and adamant etc and say a year or so after S then I can see that but otherwise, just be careful. There are so many reasons for this. It's not fair to her (she will be expecting someone without this baggage - sorry), you also might put your progress back (very far and very fast) if it does not work, you will create a position for your W to highlight and attack, your kids will be dragged into this - if W can do that (very damaging). You will become painted as the villain for definite and the kids may buy this! You don't want that.
Focus on you and the kids. That's it.
Keep going. Forget what she's up to. Don't rubberneck at her car crash, keep your eyes on the road in front.
Surfer.
M46/W40/D8/S6/T20/M12/Separated 6/2016,W takes kids Issues2009 Wpartying w/g.f's2013on EA2013PAdeniedWleavesMBR ImeetAP/EAhalts VariousBDDates MFCourse WSpew EAresumes I halt Wrages DBIng4/2016