The drug part is the inability to wrap my mind around it and make it stick. More than a significant part of me goes "There has to be some other explanation for those actions. There's no way...no one is that evil. There's something I'm missing in my asessment. Maybe I perceived something the wrong way. Maybe I'm being unfair."
I think that's a pretty common thought pattern for people who have been victimized. Contrast this with people who have not; they usually go "This guy is an asshole, and I'm kicking him out of my life immediately".
My housemate's ex-boyfriend is turning out to be a huge asshole. They broke up almost 3 months ago and she moved in here two months ago, but since finding out she's started dating again just a few days ago he has sent her something like 20 emails, all about how inappropriate it is and how she's crossed a line yadda yadda. He told our mutual friends that she's planning on prostituting herself to pay her bills, and a bunch of other sick bullshit.
It might just be a mental break from the emotional stress of the breakup, but I think he's just an asshole and this manipulative shit is probably reflective of why she stayed with him for so long... because she had poor boundaries due to having been taught at a young age that others were more important than she was, so she was easy pickings for his mind-games, and \made excuses for his bad behavior year after year instead of running for the hills like a woman with healthy boundaries and self-esteem would have.
She's much better now, which is why she finally left, and naturally he's incensed that she would DARE to leave him. And now that another man has
soiled his property
taken his ex-girlfriend on a couple of dates, he can't stop flipping out about what a bad, bad, evil woman she is.