Secondly, stop telling her you'll fight for the M.. She is going to draw out a D because she wants to keep you as a back up. You'll need to show her your happy on your own right, not tell her but show her, and ready to move on without her. Right now just keep the knowledge of the A to yourself, it isn't going to do any good to let her know you know unless your seriously ready to enforce some boundary because your not willing to be in an open R.
If she says again that M is over, just say I'm sorry you feel that way, but you should do what is best for you, I won't stand in your way.
M - 9 1/2 years 5/5/16 - Bomb drop - 3 week EA 10/31/16 - We sold house 01/10/18 - D Finalized