I just want to comment on one thing. Your thread title asks if you have destroyed all chances by beginning to DB late. What strikes me most about that question is that you sound like you are taking on the "blame" for whether your relationship comes together or ends. I seem to recall back when I first came by this board that I had the same thought. I was always someone who took on all the blame for other people mistreating me, and when my XH began his MLC, he started to blame me for all the reasons that HE was having problems. He created this list of things I was doing wrong, and I met and exceeded his expectations, so much so that he kept adding new ones to the list. And I'd keep doing what he wanted, in order to make sure I wasn't the one "destroying" the chances of us staying together.
This persisted even up to when he started to have an affair, because I immediately told him I'd work to forgive him and that I'd accept even that transgression of his. He said "you weren't supposed to say that. You were supposed to tell me it's really over now. You're messing with my head and confusing me because you were supposed to end it." Later he told me that the move to make the affair go from emotional to physical was done not just because he liked the OW but because it was "his only way out" because I'd said if I ever caught him in an affair the marriage was over."
So you see the pattern here--the MLCer will usually tell you that you are to blame for the problems that they have. Then you try to fix yourself to please them. Then even if you don't do what they expect or want, they say that's your fault too. It's all YOUR FAULT.
My XH was basically saying at the end that trying to KEEP the marriage together by being forgiving and accepting was my fault too, because his goal was never to keep the marriage intact but to run.
The reason I post this is to say that if your thread title is any indication that you are like me, you sound like you will be the type of person who will take the full blame for what's happening, and I implore you to stop that line of thinking and see that it's not your fault. Sure, there are DB things that you can do, but they are mainly to protect you and help you with detachment as MLC lasts so long that it seems most people do not achieve a reconciliation with their partner. It is very dangerous to take the blame for someone's actions on yourself. It really keeps you mired in the past which cannot be changed. I cringe every time I read someone say "If I'd just found this site earlier I could have saved my marriage."
A statement like that reflects the poster's belief that he/she is 100% responsible for the outcome, which is just never true.
I just think it's important that as you DB you keep the focus primarily on you and your sanity, and that you try to stifle the urge to take blame on yourself, if you DB and you still lose your relationship, you don't want to walk away from that feeling like you didn't do enough and take on the blame for another person's crisis. You have enough to deal with without feeling like it's "your fault."
Best of luck to you :-)
M45 Bomb 6/09; EA 6/10; Divorced 1/11 Proud single mom of 7 little feline girls and one little feline boy "Fall down 53 times. Get up 54." -- Zen saying