@MissKathleen some of the other answers here seem to see this as victim shaming, it is not, the problem in this case is not one of weakness or shame, it is that one manipulative and unscrupulous person can take advantage of a nieve partner and establish a control over them, by instilling a cycle of abuse, akin to being indoctrinated into a cult.
Such Mental Abuses use the B.I.T.E. model in the same way churches and cults do.
Getting out requires help from someone who understands, not aggression that only reinforces the abusers claims and will send you running back to their protection.
Once you have been through this, the problem goes away because you can spot someone doing again a mile away before it gets a hold upon you, however while you are trapped within it you see questioning it as an act of betrayal and further proof that you are as horrible and worthless as you have been told that you are.

@MissKathleen true, I just think we are using slightly different definitions of naive

@MissKathleen
I'm sorry you went through that, sounds like a different situation which of course is because we all have our own stories.
I'm glad you got away from such unhappiness.
I was lucky in that my abuser threw me out because she found someone else and got bored with me, had I not had two very dear friends who came to my rescue in my lowest moments I might not have recovered and rediscovered my own worth.

@MissKathleen of course I didn't.. ☺

@MissKathleen if it don't apply, let it fly.. Life's too short to put up with nonsense.. ☺

@Cutiebeauty
It is far from nonsense, it is downright evil, very real and drives too many people to their death every year, usually at their own hand since that seems, in their despair to be their only logical escape.

True but in such situations, the truth can be almost impossible to find.