There is zero evidence for her being a BPD psycho, there is tons of evidence for Dankula lusting after people (mostly male) who are not his wife very publicly.
She's the one who left him, as much as men like to pretend that women just go crazy one day and decide to get divorced "for no reason", there is usually a good reason a woman with no job prospects and two children decides the struggle of being a single mom of two is better than staying in the relationship. The fact she just gave birth to their second child means he probably did something completely atrocious. Maybe she found out she had an STD as part of prenatal screening, as is a common way for women in relationships with men who fuck other men behind their back to find out about his infidelity.