can people be held hostage in a relationship?

Yeah. I've seen both men and women completely control the lives of their partners, punishing them whenever they broke a rule and often using threats to scare them into staying. They can leave the house and such, but the fear of what might happen if they left always kept them coming back

Absolutely. Both physical and/or emotional abuse can be very paralyzing.

YES it is called Domestic violence, isolation

In some sense yes. It can also be called abuse

Yes

Not sure, but you can get addicted to a certain kind of sadness

Absolutely.

Yeah