She very well be in an MLC... unfortunately that doesn't change much for you. Your W sounds a lot like mine, and I'm pretty convinced mine in having an MLC. Again though, doesn't change a whole heck of a lot.
Understand that some/much of this is WAS/MLC script. My W said the exact same thing to me. One time while we were discussing the D/S and I became upset my W told me, "don't worry, you'll find someone else." Well that's great... I don't really want somebody else.
But it is script. It's meant to create distance between her and you, her and the family unit. There is no "final nail in the coffin" until either a) you decide you've had enough and you're done or b) she marries someone else.
You're also in the stage where you take all the blame and heap it upon yourself. This will pass. You both got here, together. You both made mistakes and have fault. Don't heap it all on yourself and don't carry her faults as yours.
Married 6 together 8 Me:38 W:31 second marriage for both SS12, SD10, S6 Bomb: 9/8/11 (day before our 5 yr ann) W moved out: 2/18/12 D final: 11/12/12 Share S 50/50. Spend as much time as I can with SS & SD