i mustve missed the episode when she came clean then. She is doing all sorts to make him think hes going mad, i assumed thats why she wanted him to be kept in hospital.
I have to admit i have missed a few episodes though so i could be wrong.
She made him doubt himself - nicked some football tickets from his back that was keeping for Boyd, then took the baby from the cot whilst Max wasn't looking and left him in his pushchair in the middle of the road. When Max had her followed, she paid of the PI and got him to put in a false report to say she'd done nothing wrong. Since he'd just been through the trauma of killing Cam, everyone assumed he was going bonkers. Self-fulfilling prophesy and all that.