Basically his team could insist she engaged with their psychologist, as she alleged abuse. But because he denied any abuse from her pre trial, he did not have to be examined by her experts.
We all saw what that did in the trial with his psychologist diagnosing her with BPD.
I don't understand how he was then able to use her abuse and the photos of injuries in his defense. Or say that she severed his finger.
At the very least that document shows evidence he is happy to lie in legally binding situations (either he lied when he signed the document, or he lied under oath)
I'm not a lawyer but that would seem to be a pretty big issue around whether the trial was fair.