There are a number if steps and my recommendations will be somewhat out of order;
1 any children? (If so do not leave marital home) 2 it is never too late to start DB. 3 give her space, let her miss you for now 4 Never bring up the A word to her again (if you want to save M) 5 you will stumble during DB so start fresh every new day 6 do not push any counseling on her (individual, marriage etc) 7 on the apt - you can have a civil conversation about this as money is involved, and always remember to stick to short and non emotional topics 8 accept your contributions to the current state if your M, its difficult but you also need to forgive yourself 9 your W is already starting 180s, so start some yourself. Chances are this A won't last long so when she likely is no longer emotionally occupied you can be buff and tan and get her back.
Stay positive, you control your level of happiness.
"Don't chase people. Be yourself, do your own thing, and work hard. The right people - the ones who really belong in your life - will come to you. And stay." ~ Will Smith
