It is. Another piece of the very complex puzzle is pride. It's really hard, especially for a bright, independent person to go to their family and say "I fucked up so badly. I married an abuser and I'm being abused." One of the reasons that's so hard to do is because of statements and questions about how could one *possibly* stay in that situation. How did you allow yourself to be manipulated that way??
In my case, and again, I stress it wasn't mostly a physical thing, it helped that when I put my son in therapy so he'd have a neutral adult to talk to during the divorce process, his therapist identified my ex as a sociopath (he'd met him and spent several sessions with him). I had all those same questions - how could I have let this happen? What red flags did I miss? How could someone like *me* have ended up this way??
He told me that my ex was a sociopath, and they are masterful at what they do. He said that there *were* no red flags I missed, that there was no way for me to know what my ex was until he chose to show it to me. I had a really hard time coming to terms with that, and it took some time.
Sociopaths are NOT identifiable up front. That's their stock in trade. In fact, they are charming as all hell.
