For those struggling with the adultery and hearing about soulmates and blah, blah, blah... It's not what you think. It's empty and offers only the illusion of a carefree life--Know that. No matter how much they may try to convince you otherwise.
To read of your sitch and especially the timeline is a little daunting for someone who's only 18 months post-BD, though I take comfort in what you say about the OP. From afar the OM in my sitch seems to have it all but on closer inspection: Never married; No children; No contest... my Ss will always be my greatest adventure/achievement.
I'm glad to hear of where you are currently and that with recent ex-H's communication you can finally lay any remaining self-doubt to rest.
Me 50, ExW 49 T21, M13+ S15, S13 BD #1: 25-Jan-2016 (EA confirmed & ILYBINILWY) Sept-2016 Mediated Sep. starts Oct-2016 W petitions for D Jan-2017 R w OM admitted/confirmed Jun-2018 D'd