Another's aberrant behaviors always force us to check-in with our own reality. When we can't RELATE to their actions or reactions, we naturally wanna mentally make sense of em, so we can excuse those odd behaviors (especially when we've come to care about em).
Please understand, you've been doing this since childhood, when events in your home felt bad and didn't make rational sense to you. You tried really hard to make allowances and excuses for your parent's behaviors, so that you could keep loving em and stay attached.
You did a hellova job with that, but it's become the blueprint you're still working off of, in context of ALL your relationships. Every child has a fierce need to feel safe and secure. When something or someone threatens this, he/she feels confused and unsafe.
Our emotional well-being DEPENDS on us being able to mitigate our confusion, and we'll do literally ANYTHING to bring this about, because confusion = instability, and we have an instinctive need for stability, as kids.
An unstable relationship in adulthood literally replicates our struggles to feel secure and 'safe' in childhood. These are well-worn, familiar emotional sensations we grew up with, so we identify and relate to them as "normal." They're NOT of course, but they're mimicking our only frame of reference for emotional interaction, so how could we possibly know any better than to WANT this kind of experience??
I've said it before and I'll say it again: There's no fucking way on God's green earth, you'd be attracted to people with personality disorder features, unless you were raised by a woman who had 'em. You'd want only secure, safe, reliable, nourishing, mutually loving and respectful relationship interplay. You would NOT be intrigued by people who made you feel a little uneasy, hungry for love or unsafe.
A sense of 'danger' is exciting and compelling for a lot of people who grew up without the ability to emotionally rely on a parent for their care. Subtle feelings of threat or danger became part of their Attraction Strategy, and they're automatically drawn to these sensations in adulthood.
If this is YOU, you're bored by someone who doesn't activate these learned emotional responses in you, which (again), replicate the ONLY feelings you learned as a child, to associate with loving someone. Getting well, means connecting to yourself in new and wholesome ways, so that you're no longer attracted to people who cannot return your adoration~ no matter HOW enticing they seem to you.