He extorted a huge amount of money from her and she was virtually a prisoner in her own home.
This is appalling. As a previous poster said, there are often mental health issues (personality disorders) involved. In the case you mention or also regarding the sordid Fritzl case (he locked up his own daughter and the children she bore him over the years in his own cellar ffs) it very much sounds like unabashed sociopathy, in the case of this woman and transwoman here, I'm wondering if (as an alternative to a sociaopathy explanation) they might actually believe their own bullshit and see themselves as victims, borderline style.
I will say that I find the psychology of the victims fascinating, who so gullibly fall for it (not people like Fritzl's daughter obviously. She was literally locked up). I mean, the indifference of this professor towards his own family is also something to behold. How could a document about potentially borrowing 500,000 $ against his and his partner's (!) house 'end up' on his desk, where his partner discovered it? This was most certainly put there by himself. (There might be some lesson here that is relevant for feminism about a man being totally subservient to the identity politics weaponizing scammers while fully ignoring the material rights and property of his own partner).