Just my thoughts...
I hope you get more responses from those that have BTDT successfully (or peacefully).
Our big Dday occurred 18 months after the A ended, so that may make a difference for some. It was the day that he finally started telling the truth, finally starting "owning his shit", finally started being real. (Because I got an anonymous letter, it was NOT a confession--that likely never would have happened and we would still be in that inauthentic life).
Instead of dreading the day I actually looked forward to it and now have some lovely memories. It really highlighted how much he had changed over the previous year, and how far we had come as a couple.
Good luck to you.